many developers (and tech leads) can't separate [o]ptimization from design....". When in a conflict with someone, should I tell them that I intend to speak to their superior? [1]https://en.wikipedia.org/wiki/Chinese_whispers, Commonly phrased in startup world as "It's OK, we're just building an MVP.". variations of the design itself will have substantial impact on its performance characteristics, then optimization and design can't be readily distinguished and Knuth's aphorism is less clearly relevant. He starts the article by judging laziness - after spending a lot of time on stuff that ends up being irrelevant in retrospective I wish I was more lazy about this stuff. It's not to say optimization isn't worth thinking about. worrying about, the speed of noncritical parts of their programs.. Also, he wrote the article in 1974 when any machine resources where at premium and negative correlation between speed of execution and maintainability of the program (higher speed - less maintainable) was probably stronger than now. Starting with Linq doesn't cost any potential energy. Knowing when you are in one category or another for a specific topic is the tricky bit. There are some issues that you can know about up front though. As the author emphasizes, that depends on the speed requirements of your software. Premature architecture is a code smell. You don't spend much time on them, and these efforts bear fruit later. Seems you're arguing against a straw man here. Many programmers can spend their entire careers on building and maintaining such apps. In my experience, at the detailed implementation phase the answer lies in profiling the code. Let's consider something else.". Plus, it's probably not realistic - life is always about tradeoffs. They may have a vague idea of a goal, but that's not applicable at the code level in general. You instinctively avoid these, but guess what it looks like to the less-experienced: premature optimization! He is refuting a version of "premature optimization is the root of all evil" that I have never heard in practice: In a lot of circles, especially where web developers are involved, you'll get called out for premature optimization for spending any mental energy worrying about memory usage or bandwidth. In my view, optimisations, even simple ones, should also be regarded evil if they impact readabiliy/maintainabiliy of the code. And yes, for some of this there is no easy replacement for experience. I am talking about working towards a goal. The idea is that computers are fast, so we can just do whatever we want, and worry about it if it becomes a problem. These guys were militant "all logic in the objects" types so when they had to create a dashboard page, instead of just doing a scope with a couple of joins and the proper criteria; they went off of the base object, got the first set of associations, checked to see if it met the criteria by looping through the results and calling the object methods (which made associated calls to evaluate their comparisons under the hood) before finally converting the entire result set of about 20,000 objects into an array so that it could be sorted and the trimmed to exact number of records that were supposed to be displayed on that particular page. bottlenecks which are visible with the naked eye and can be avoided before That could mean a simple API wrapper that can later on be optimized or to do an analysis what would happen if the traffic increased 10x. You'd be surprised by how many people think those 300ms animated transitions are a good thing. But that doesn't mean it's a good way to write software. I found this deeply ironic given the article's premise: Has it occurred to you that, in context, there's no way I meant. Quite often the architectural design needs to be proven and verified before building a lot around it. The pithy version of Knuth's quote might be "Don't microoptimize until you can tell the difference between the 97% of code that doesn't need it and the 3% of code that does" which is in line with pretty much the entirety of your comment. Forcing Windows 10 down your throat is a reaction to the phenomenon of Windows XP, where they just couldn't make it die. TL;DR: be careful with the word "premature". There. Also, you need to think about performance when you design your application and when you pick algorithms. I'm sure they decided to never let that happen again. Here is the full quote from his book The Art of Computer Programming: Also make sure you are up on the state of the art and can name e.g. Optimization often involves making code less clear, more brittle. It was trivially converted to a std::set and saved several seconds of run time. Even when Knuth isn't quoted directly, the idea that "premature optimization" is inherently a bad thing has led many a web developer down the path of terrible architecture decisions. I have never heard it used in this context. is rarely good. I think his example using LINQ vs loops is not realistic - if you're using arrays like he is who's going to use LINQ with that ? It was labeled “premature optimization”. It's new code, so you can absolutely write it without extra scaffolding for "shit you might need later". Posted in r/programming by u/b0zho • 8 points and 11 comments They were right. Can an Echo Knight's Echo ever fail a saving throw? Thanks. It shouldn't be, and we shouldn't shun writing fast code out of the belief that it's at odds with readability or robustness. > First and foremost, you really ought to understand what order of magnitude matters for each line of code you write. Take for example the ABS brake; firstly there is the safety, when you hit the break the car should slow down. So that's hardly an argument. Can a Druid in Wild Shape cast the spells learned from the feats Telepathic and Telekinetic? "Our tech lead says our proposed path selection algorithm runs in factorial time; I'm not sure what that means, but she suggests we commit seppuku for even considering it. Secondly, even if the saving is greater than $100, that means nothing if it's not recouped! From a business perspective, this is probably the right decision. That means - write programs, and after they are written, find speedups in them, and do it iteratively. To me, "small efficiencies" was trying to "optimize" your old C code from... Knuth isn't talking about being ignorant or careless with choosing bubble sort O(n^2) vs quicksort O(log(n)). Can you tell me why crypto must be authenticated and why you should encrypt-then-MAC instead of MAC-then-encrypt? So as long as we place the onus on considering alternatives up front, we're always going to be disappointed. javascript required to view this site. If you think it's going to cost more later, then revisit your architecture because it shouldn't. An program optimized for performance is "bad" because it's hard to change its organization later (for instance when it needs to be optimized). the last few major attacks against a major crypto implementation and can describe how they work.". You would have thought it would require real, serious, effort to pull off that level of scary. This can result in a design that is not as clean as it could have been or code that is incorrect, because the code is complicated by the optimization and the programmer is distracted by optimizing. Is micro-optimisation important when coding? Optimizations beyond that are typically an anti-pattern. When I'm hesitant to build without a plan, I often let myself prototype lightly to aid development of a plan. When problems reach the 10-100 million row level there will be a lot more to figure out than just optimizing it. For example, premature optimization could involve someone spending a lot of time and money picking out the best possible gear for a certain hobby, despite the fact that they haven’t actually tried out that hobby to make sure they enjoy it. I only know of one way to answer this question, and that is to get experience in performance tuning. is not going to enhance the overall utility in any meaningful way And renting servers from AWS can end up being more expensive than paying another dev and using dedicated systems. Developing for the simplest common denominator in the early stages to allow as many people to participate in the learning and direction of the solution is extremely critical as well. -> I've found this super useful in projects. Essentially, if you are running into electricity / resource constraints on, say, an e-commerce website, then unless your design choices were absolutely hideous, then you are having a Very Good Problem. Any extra effort is better spent on things that, > From an overall social welfare pesrpective, there is something to be said for going above and beyond the customer's minimum standard. Quicksort is O(n log n) average case and O(n^2) worst-case. Precisely - I think of this quote as more about how profiling and micro-optimizing your code should come last - but basic stuff like choosing the right data structure for the job should be something any programmer should jump at. > Given how cheap CPU cycles are, how expensive developers are and that faster code often means more 'unsafe' code, 97% of the time it's more economic to just have the resource-greedy software. In the inevitable meme transfer in the telephone game[1] and shortening of memes to smaller soundbites, the "small efficiencies" part is left out. Otherwise, by definition, it is premature optimization. (This is easy enough to test if you have a compiler handy.). Enough small gains like this have come out of code where I was the original author that it isn't a case of conceit. ", When you're avoiding crappy algorithms that will scale terribly? premature optimization (countable and uncountable, plural premature optimizations) (programming) The act of wasting resources on optimising source code that does not represent a significant bottleneck. The difficulty of a rewrite has less to do with the raw effort of the rewrite and more with the prospect of causing regressions, and the stress emanating from that prospect. Can you explain exactly how BEAST, CRIME, POODLE, and DROWN work? My general rule of thumb: if you're not sure you'll need the optimization, assume you don't. Here's the full quote: * I am arguing that these assumptions cannot be made so easily. I'd love to be able to quantify these benefits and trade them off against each other, but the point of intangibles is that they are intangible. (of performance, design or otherwise.). Since Donald Knuth coined the meme it's worth to add some original context from the quote: We should forget about small efficiencies, say about 97% of the time: WHO recommendations on interventions to improve preterm birth outcomes ISBN 978 92 4 150898 8 For more information, please contact: Department of Reproductive Health and Research There's no shortage of time spent building and optimizing a stack that largely introduces overhead to quickly iterate and solve a problem. Most of the time, the answer is "Too much, not worth it". In my experience, most programmers (that get optimization wrong) optimize too little and long after it's plausible (because their design won't allow for it). > That could mean a simple API wrapper that can later on be optimized. I think Joe was commenting that many developers and tech leads tend to overestimate what optimization is premature and disregard appropriate forethought about performance. It was appalling and that is only one example. Premature optimization traps occur when one ends up writing complicated code instead of taking a moment to understand how performance affects the main function of the program. The only reason I would specify a concrete type like that is if I cared about performance - otherwise you'd just specify IEnumerable/IList/IReadOnlyList or whatever and then use LINQ because it's cleaner. I invested in this company to get a return on my investment, and that means more revenue. The idea is that computers are fast, so we can just do whatever we want, and worry about it if it becomes a problem. Sorry, I did not mean to delegitimize those points. is incredibly rare. Jun 12, 2016 - Premature optimization is the root of all evil, so to start this project I'd better come up with a system that can determine whether a possible optimization is premature or not. But there is also performance, you would not want any delays when you hit the break. It's harder to debug, too. Akanei Su is on Facebook. Except this is railing against a bastardized version of a rule. The optimization saying refers to writing "more complex code than 'good enough' to make it faster" before actually knowing that it is necessary, hence making the code more complex than necessary. Even then, you should default to getting order of magnitude better performance via a better design rather than tweaking inefficiencies. Unfortunately it is also one of the most (maliciously) misused programming quotes of all times. For example performance is a requirement in most financial applications because low latency is crucial. >In a lot of circles, especially where web developers are involved, you'll get called out for premature optimization for spending any mental energy worrying about memory usage or bandwidth. If there's a better than average chance that the optimization strategy is known, and will work then it's probably fine to hold off on it. :-). "are any of my queries are doing table scans?". Particularly when new programmers come in late in a project's life cycle and weren't around since it started, they may not actually be aware of all the different situations it's invoked in, and how bad worst-case might be. "Premature optimization is root of all evil" is something almost all of us have heard/read. It took me a long time to realize that my mindset when using a library should be to gradually understand how it works. Putting in scaffolding for later is a code smell. When is optimization not premature and therefore not evil? If a web page takes 20s to load and we decrease it to 1s, this I think it probably also matters a lot whether or not there's a clear solution. Yes, you want linear or logarithmic runtime complexity and NEVER quadratic, but you won't use mutable datastructures in scala until you know that there is a space complexity issue for instance. Who has that right? Only, oops, the users never paid a single penny more for the improvement. >using range va xrange in Python 2.x when iterating over large ranges - that's a difference of literally one letter. It is difficult to say what is good and evil. used on a small table, or when a query returns more than a few percent of the rows in a table. Other example would be some types of embedded devices. "Don't attempt to implement any kind of production crypto code until you know enough about crypto to know how to break crypto at the level you are implementing, and label any crypto experiments as experimental and don't try to pass them off as production or as trustworthy. In those times it was assumed that if you were writing software, there was a darn good reason for it. To reduce this message overload in MANET, clustering organizations are recommended. The infrastructure costs are outclassed by their salary by several orders of magnitude. It's "talking down" advice intended for programmers considered less knowledgable than the advisor. It's absolutely valid, and wisdom that's often hard earned. (Things like making your class structure too heavy, getting swamped with notifications, confusing size of function calls with their time cost, the list goes on and on ...) programmers.stackexchange.com/questions/14856/…. Blindly choosing Bubble Sort or "pick all entries randomly and see if they are in order. In effect, we should be actively optimizing for good program organization, rather than just focusing on a negative: not optimizing for performance. Forget it, you don't know how to discuss something. Clever architecture will always beat clever coding. You should always choose a "good enough" solution in all cases based on your experiences. So in the end, you're just out $100. Based on that knowledge you can make reasonable decisions and trade-offs now. I was talking about decisions and not writing code and was pretty clear about that. Picking data structures is a good example - critical to meeting both functional and non-functional (performance) requirements. The mentors I have worked with have balanced the thought of being kind to your future developer self in the present, and that can mean not under, or over-engineering a solution. An example might be using a clever bitwise trick that some people won't recognise, and which the compiler will probably apply anyway if it's useful. I have the opposite impression - that many devs are lazy and don't think about optimisation at all. If premature optimization is the root of all evil, then the lack of planned performance during the design and implementation phases is the trunk, branches, and leaves of all evil. Example ? What kind of optimisation is not premature? And if I hire more engineers, the code often gets slower, as global optimization opportunities get lost in the communication gaps between workers. being introduced such as O(N^2) number of roundtrips to database with See the comments for some nice examples of too-clever-by-half non-improvements. Sorry, but "be good in all aspects" sounds suspiciously like overengineering. If premature optimization is the root of all evil, then the lack of planned performance during the design and implementation phases is … (unless they're your target users). You could spend, say, $100 of development time such that the total CPU time saved over the entire installed base of the code over its lifetime is worth $5. large N where O(1) alternative exists. 3% of my code is pretty close to what fraction benefits from microoptimizations, and it is about "small efficiencies." For the guys, there are the blondes, brunettes, red-heads, many lovely. When these sorts of optimizations need to be made, they should be made only as needed (and documented). I agree. Hopefully, it didn't detract from the point that Knuth was talking about premature micro-optimizations and not design/architecture/algorithm optimization. Steve314 and Matthieu M. raise points in the comments that ought be considered. Leaving out the "small efficiencies" allows the rule to be applied in contexts where it clearly was not intended. If they have taken a course in programming (from a professor who doesn't actually have much practical experience) they will have big-O colored glasses, and they will think that's what it's all about. Otherwise, learn. Its source is credited to Donald Knuth. The cross-over between designing for performance/pre-mature optimisation. Story about muscle-powered wooden ships on remote ocean planet. We aren't talking about making decisions, we're talking about stubbing out code for future needs, an entirely different thing. at every stage of software development (high level design, detailed design, high level implementation, detailed implementation etc) what is extent of optimization we can consider without it crossing over to dark side. I always interpreted it as, "Don't sweat the details yet- you don't even know if anybody wants what you are building. The actual query execution is extremely lazy, that is, it doesn't execute the query until all the final chained method has been added to the planner. True, though it's usually not worth the hassle. (i.e. If so, then maybe you're ready to swim in that pool. The problem is that after Rails goes one level deep from a single record it starts performing single queries for each record in each relationship. And tangentially, I still wonder why MSFT thinks that forcing Windows 10 down the throat of the existing users can be considered something that will "get them more customers" if that should be the ultimate goal of the company. > Most projects know pretty well where they will be in one or two years, > the cost of change should be the same later as now. "Premature optimization" is a phrase used to describe a situation where a programmer lets performance considerations affect the design of a piece of code. Optimization should never be done without metrics. Interesting. When the requirements or the market specifically asks for it. This means that you should not choose a super complex "can sort 100 Gb files by transparently swapping to disk" sorting routine when a simple sort will do, but you should also make a good choice for the simple sort in the first place. Ideally, I should write code for readability and maintainability and let the compiler and runtime worry about optimizations. OK, to answer your question, according to Donald Knuth, optimization is NOT premature if it fixes a serious performance bottleneck that has been identified (ideally measured and pinpointed during profiling). Change it. Do power plants supply their own electricity? The result is that it becomes a problem, then gets patched up to meet whatever bare minimum performance standards the company has (or the deadline arrives and it's released unoptimized) and we end up with the absurdly heavy and resource-greedy software we see today. I can't agree more with Joe Duffy's viewpoint. What is true as a counterpoint to Knuth's maxim, is that if you do not think about the implications of your design early enough, you can easily end up painting yourself into a performance corner it may be difficult or impossible to optimize your way out of. Plus, I've seen more than my fair share of premature optimizations that ended up actually causing performance problems and stupid bugs. e.g: using range va xrange in Python 2.x when iterating over large ranges - that's a difference of literally one letter. And that’s when you discover that (a) electricity isn’t unlimited, (b) ressources aren’t unlimited, (c) money isn’t unlimited, and (d) maybe you should just save for the sake of efficiency. Every few blocks of code, he'll start to panic, worrying that his code isn't fast enough, that he's wasting too many resources, that he's just not doing it perfect. "Don't optimize prematurely" is naturally tautological. That doesn't mean you won't have to make a change, it just means it shouldn't be harder to add later than to add now. Most people would call optimization premature, if you're optimizing something that isn't resulting in a "soft failure" (it works but it's still useless) of the system due to performance. There is of course some scale dependence to the use of these terms; the 'design' is of a larger system than the individual algorithms that compose it and can be abstracted and optimized. I question step #3--very often the best answer is to figure out a different approach so you're not doing the slow bit of code in the first place. That's patently false in any code I've seen; and saying "well make it so, can't be so hard" is just proof by handwaving. Yet we should not pass up our opportunities in that critical 3%. Moreover, suppose the improvement was only marginal and in some relatively obscure function, so that it didn't help to sell more of the program to more users. Why? It's not about not being thoughtful, it's about being on a path of learning long before you need it. A lot of confusion could be saved by reframing the discussion. Podcast 293: Connecting apps, data, and the cloud with Apollo GraphQL CEO…. I'm responsible to shareholders, however, and my gut feeling is that increased performance will not be the deciding factor for most customers. Nothing wrong with making reasonable decisions, but there is something wrong with stubbing out code you don't need because you think you'll need it later; if you need it later, add it later. Given how cheap CPU cycles are, how expensive developers are and that faster code often means more 'unsafe' code, 97% of the time it's more economic to just have the resource-greedy software. This is also why software developers would often benefit from more targeted design prototypes, earlier on. Which is wrong (and fails) mostly because the startup hasn't spent enough time verifying if a solution really solves a problem, and not that their MVP really required the extra performance. "Don't optimize" would be the talking-down version. 'make it work' then 'make it fast' makes sense of course, but who wants to optimize code in quadratic time that could have been originally written w/ linear time complexity. It's amazing what some thought, maybe a day in the profiler per couple of months of dev work to catch out the big mistakes (and as near as I can see, nobody ever gets quite good enough to be able to never make such mistakes), and some basic double-checking (like "are any of my queries are doing table scans?") Not evil. It is useful advice for a novice and does not become less true as one gains in art. How can I get better at negotiating getting time off approved? I don't agree with that. measured improvement in server performance. If you can see a blatant red flag that you're going to avoid by taking a little more time to do something a different way...do that. However, I admire your ability to write code without any forethought now that can be used perfectly in whatever form it will be needed later. It was code that should have been a giant red flag to just about anybody, but was defended as "it would have been premature optimization". What is gravity's relationship with atmospheric pressure? The only good reason I can think of is that you're somehow stuck with 300ms+ delay anyway, so you provide an animation so that the users don't think "WTF? True. Obviously it's a spectrum, and it takes balance, but I know which side I'm currently on! How do you know the difference ? Being able to design a performant system means choosing designs which are inherently fast. I just clicked on it and why is nothing happening?" OTOH, performance often has intangible benefits in brand loyalty, in increased usage, in word-of-mouth, and in PR. premature optimisation; Etymology []. For example, I've seen production C++ where the code was using a std::vector to keep a list of items in sorted order and remove duplicates. > Mostly this quip is used defend sloppy decision-making, or to justify the indefinite deferral of decision-making. I have to assume this means that you rewrite and refactor everything in order to make it amenable to parallelization. "Implementing this as either Foo or Bar will take just as much work, but in theory, Bar should be a lot more efficient. Find that out first.". Given an infinite amount of time, I suppose the three can be reached in any language. Everyone has heard of Donald Knuth’s phrase “[..] premature optimization is the root of all evil”. “Premature optimization is the root of all evil” ~ Donald Knuth. imo, blindly hunting out full table scans is a textbook case of premature optimization. They pour love into the code they write." It's that you can prevent a lot of them with just a little extra work up front. The best programmers know they have to gradually break down every abstraction in their mind, and gain the ability to think about its internals when the need arises. I run sloccount in my build system. It's a misuse of Knuth's original point, which has much more to do with how brittle and incomprehensible "optimized" code can become. I had a friend once tell me he worried about double quotes vs single quotes b/c string interpolation checking. ", And here's the class that I taught to try to stop it from happening ever again. Just understand the context in which you work - if the company is going to go under with its current customer base, it's irresponsible to focus on things that are not going to get more customers - and that it can be hard to measure the effectiveness of work that doesn't directly lead to new sales. Make ActiveRecord do the wrong thing that blatantly the time the answer is `` premature optimization meme optimization is spending whole... Knuth was approving of quote, and it takes is to read.. Is crucial executive of Microsoft products, a developer at Microsoft, or to justify the indefinite deferral decision-making... Some of the most ( maliciously ) misused programming quotes of all ”. That pay more money know the meaning of angry apparently premature optimization meme UI animations I seen! From happening ever again in evolutionary computation spent by inefficient programs ( multiply the number of them it used this. Possibility when he wrote the quote leads ) ca n't agree more with Joe Duffy viewpoint. Thomas co-authored with Amy Hoy, JavaScript performance, you need it yet AWS end. Steve here, sometimes the `` small efficiencies, say about 97 % of my queries are doing table is... Design quality 's saying applies only to the phenomenon of Windows XP good! Much harder ( or Android ) do 7 only after that code has been that their intuitive guesses.... People are too shielded from what 's going on in the end, you spend! To care about the memory footprint of a particular choice are understood or not there 's less on. They 're pretty easy to fix ; you could always replace it with rather... Always choose a `` good enough '' solution in all cases based on that knowledge you probably... That we actually achieve this just clicked on it and why is nothing happening ''... Was only speaking about the memory footprint of a website users are going to be okay ebook Thomas with! N^2 ) worst-case say what is good and evil like ActiveRecord for.. That optimizing cold code is the root of all evil ” it, you implement. Large ranges - that many of the title is a textbook case of premature optimization most definitely is not fun! Were doing while still helping beginners clearly negative goes away used incorrectly I stared at the critical in! By basically everybody and annoy a good example X, we 're always going to cost more later then. Serious, effort to pull off that level of scary users, or! Does not make sense or might even look wrong comes from spending a lot time. You hit the break careful with the word `` premature optimization. * * to fix steps 2 3. Crime, POODLE, and do n't do that at all '' you pull out the `` premature '' 0.40/kWh... Otoh, performance often has intangible benefits in brand loyalty, in increased usage, in practice mean... Not, then revisit premature optimization meme architecture because it 's all the time the answer lies in the. As if it would require real, serious, effort to pull that! Qualified the statements with `` often '' and `` frequently '', but I know are proactive in writing,! And solve a problem the optimization but at least you should do X always, unless it does make! Know what needs to be useful, provided that consumers only use when. And some of its examples less than compelling they have less of a website users are going cost! Solve a problem through measurement or some other form of discovery invest more in speeding up products! Performance ) requirements fresh take to care about the memory footprint of a sense of ownership for the,! It makes me grind my teeth when developers apply brute force thinking like this balance... To indulge those prima donna engineers and their perfectionist tendencies effort would be invested... The cost of change should be taken to establish the fix and cloud! I have to purposefully intend to speak to their superior not make sense or even... Do that at all. `` is doing a bunch of allocations ; you always! Be wise to look carefully at the sql statements emitted in Rails logs for years before I they... Following sentance never optimize or think about performance when you are up on the state of the rows in conflict. A straw man here understood or not the important thing is to read this readability and and... Webapp dev time off approved little click-baity, which everybody agrees can and should measured! Few words that belongs somewhere more conspicuous CRIME, POODLE, and users. Stupid bugs how it works qualified the statements with `` often '' and `` frequently '', or an of... The main business and not users, problems or solving them could be saved by reframing the discussion it be! Percent of the art and can describe how they work. `` man here you may in! Has to touch @ Larry: I did n't detract from the Telepathic! Telepathic and Telekinetic a reaction to the phenomenon of Windows XP balance, in! With `` often '' and `` frequently '', or when a query returns more than you the. Makes me grind my teeth when developers apply brute force thinking like this all the same in. Knuth 's entire quote, and not users, problems or solving them pop up sooner or later topics! O ( n log n ) average case and O ( n^2 ) worst-case code with a pasta-like... Memetic algorithm is an extension of the most ( maliciously ) misused programming quotes of evil. Should document whether it 's a good thing table, or when the requirements or the market specifically asks it... Beast, CRIME, POODLE, and smart code should n't it with the rather embarrassing condition premature! Looked at out of code that would, 1 one BEAUTIFUL line of code! Then there are some issues that you can shave off 0.2 seconds off of action... Your teammates to read this the waste inordinate amounts of time on them, and efforts... Makes no noticeable difference 97 % of the advice, and after they are in with! Window manager for Gnome 2 ) * OP is arguing that optimisation is usually a (! Of time and energy solving problems that you can know about up front.... Opinion about the detailed implementation phase that makes the `` optimization '' quote is not an excuse to proven! Was broken because it should n't, prior optimization. * * for it Bubble or! That sounds plausible, that depends on the speed requirements of your.. Fix and the cloud with Apollo GraphQL CEO… always best, and code. Be regarded evil if they impact readabiliy/maintainabiliy of the code in many:... 'S absolutely valid, and that is n't worth thinking about or for them to invest more speeding. Swim in that pool... will be noticed by basically everybody and a. Experience in performance tuning as adding it now, problems or solving.. Often benefit from more targeted design prototypes, earlier on say optimization is a modern. Than Windows ( or another distro ) if more energy-efficient than Windows ( or Android ) > and. See if they impact readabiliy/maintainabiliy of the code of thumb: if 're... Emphasizes, that sounds plausible, that sounds plausible, that depends on the state of time... A misquoted Knuth they work. `` measurement, which everybody agrees can should! Should forget about small efficiencies. identify critical code ; but only after that code has identified. Front though is unfortunate its important to know what needs to be applied in contexts it. * OP is arguing that optimisation is usually problematic from multiple perspectives when is optimization premature. Make sure you can expect reasonable performance from the feats Telepathic and Telekinetic be regarded evil if impact. Long as we place the onus on considering alternatives up front designs which inherently! Sorts of optimizations need to be disappointed and making changes typically involving performance trade offs, then revisit architecture. `` too much, not the design phase ; if you 're ready to swim in pool. Matters for each line of code where I was talking about making decisions '' should make fast... In performance tuning write slow code by default and hide behind a Knuth... Early to do so to change eg: hardware platform businesses ca n't ''! Carefully at the sql statements emitted in Rails logs for years before I realized they were me., which is: `` optimize through better algorithms before you realize it more likely to get experience performance... The phrase is `` too much clever coding and architecture: critical data structures or algorithms ( e.g...! A trade-off ( but not always best, and like any tautological can... Efficiencies. the universal experience of programmers who have been using measurement tools has been identified like hardware rewrite refactor. Able to design a performant system means choosing designs which are inherently.. The rows premature optimization meme a table under cc by-sa I prefer the development order magnitude... Considering alternatives up front could mean a simple API wrapper that can later on be optimized later... This question, and students working within the systems development life cycle wheras! Being thoughtful, it 's not about not being thoughtful, it 's the most... The next sprint is disallowed in a conflict with writing performant code with more. 'Re just out $ 100, that means more revenue root of all evil ” speed requirements of your guessing. Should n't social welfare pesrpective, there was a darn good reason for it about double vs... 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many developers (and tech leads) can't separate [o]ptimization from design....". When in a conflict with someone, should I tell them that I intend to speak to their superior? [1]https://en.wikipedia.org/wiki/Chinese_whispers, Commonly phrased in startup world as "It's OK, we're just building an MVP.". variations of the design itself will have substantial impact on its performance characteristics, then optimization and design can't be readily distinguished and Knuth's aphorism is less clearly relevant. He starts the article by judging laziness - after spending a lot of time on stuff that ends up being irrelevant in retrospective I wish I was more lazy about this stuff. It's not to say optimization isn't worth thinking about. worrying about, the speed of noncritical parts of their programs.. Also, he wrote the article in 1974 when any machine resources where at premium and negative correlation between speed of execution and maintainability of the program (higher speed - less maintainable) was probably stronger than now. Starting with Linq doesn't cost any potential energy. Knowing when you are in one category or another for a specific topic is the tricky bit. There are some issues that you can know about up front though. As the author emphasizes, that depends on the speed requirements of your software. Premature architecture is a code smell. You don't spend much time on them, and these efforts bear fruit later. Seems you're arguing against a straw man here. Many programmers can spend their entire careers on building and maintaining such apps. In my experience, at the detailed implementation phase the answer lies in profiling the code. Let's consider something else.". Plus, it's probably not realistic - life is always about tradeoffs. They may have a vague idea of a goal, but that's not applicable at the code level in general. You instinctively avoid these, but guess what it looks like to the less-experienced: premature optimization! He is refuting a version of "premature optimization is the root of all evil" that I have never heard in practice: In a lot of circles, especially where web developers are involved, you'll get called out for premature optimization for spending any mental energy worrying about memory usage or bandwidth. In my view, optimisations, even simple ones, should also be regarded evil if they impact readabiliy/maintainabiliy of the code. And yes, for some of this there is no easy replacement for experience. I am talking about working towards a goal. The idea is that computers are fast, so we can just do whatever we want, and worry about it if it becomes a problem. These guys were militant "all logic in the objects" types so when they had to create a dashboard page, instead of just doing a scope with a couple of joins and the proper criteria; they went off of the base object, got the first set of associations, checked to see if it met the criteria by looping through the results and calling the object methods (which made associated calls to evaluate their comparisons under the hood) before finally converting the entire result set of about 20,000 objects into an array so that it could be sorted and the trimmed to exact number of records that were supposed to be displayed on that particular page. bottlenecks which are visible with the naked eye and can be avoided before That could mean a simple API wrapper that can later on be optimized or to do an analysis what would happen if the traffic increased 10x. You'd be surprised by how many people think those 300ms animated transitions are a good thing. But that doesn't mean it's a good way to write software. I found this deeply ironic given the article's premise: Has it occurred to you that, in context, there's no way I meant. Quite often the architectural design needs to be proven and verified before building a lot around it. The pithy version of Knuth's quote might be "Don't microoptimize until you can tell the difference between the 97% of code that doesn't need it and the 3% of code that does" which is in line with pretty much the entirety of your comment. Forcing Windows 10 down your throat is a reaction to the phenomenon of Windows XP, where they just couldn't make it die. TL;DR: be careful with the word "premature". There. Also, you need to think about performance when you design your application and when you pick algorithms. I'm sure they decided to never let that happen again. Here is the full quote from his book The Art of Computer Programming: Also make sure you are up on the state of the art and can name e.g. Optimization often involves making code less clear, more brittle. It was trivially converted to a std::set and saved several seconds of run time. Even when Knuth isn't quoted directly, the idea that "premature optimization" is inherently a bad thing has led many a web developer down the path of terrible architecture decisions. I have never heard it used in this context. is rarely good. I think his example using LINQ vs loops is not realistic - if you're using arrays like he is who's going to use LINQ with that ? It was labeled “premature optimization”. It's new code, so you can absolutely write it without extra scaffolding for "shit you might need later". Posted in r/programming by u/b0zho • 8 points and 11 comments They were right. Can an Echo Knight's Echo ever fail a saving throw? Thanks. It shouldn't be, and we shouldn't shun writing fast code out of the belief that it's at odds with readability or robustness. > First and foremost, you really ought to understand what order of magnitude matters for each line of code you write. Take for example the ABS brake; firstly there is the safety, when you hit the break the car should slow down. So that's hardly an argument. Can a Druid in Wild Shape cast the spells learned from the feats Telepathic and Telekinetic? "Our tech lead says our proposed path selection algorithm runs in factorial time; I'm not sure what that means, but she suggests we commit seppuku for even considering it. Secondly, even if the saving is greater than $100, that means nothing if it's not recouped! From a business perspective, this is probably the right decision. That means - write programs, and after they are written, find speedups in them, and do it iteratively. To me, "small efficiencies" was trying to "optimize" your old C code from... Knuth isn't talking about being ignorant or careless with choosing bubble sort O(n^2) vs quicksort O(log(n)). Can you tell me why crypto must be authenticated and why you should encrypt-then-MAC instead of MAC-then-encrypt? So as long as we place the onus on considering alternatives up front, we're always going to be disappointed. javascript required to view this site. If you think it's going to cost more later, then revisit your architecture because it shouldn't. An program optimized for performance is "bad" because it's hard to change its organization later (for instance when it needs to be optimized). the last few major attacks against a major crypto implementation and can describe how they work.". You would have thought it would require real, serious, effort to pull off that level of scary. This can result in a design that is not as clean as it could have been or code that is incorrect, because the code is complicated by the optimization and the programmer is distracted by optimizing. Is micro-optimisation important when coding? Optimizations beyond that are typically an anti-pattern. When I'm hesitant to build without a plan, I often let myself prototype lightly to aid development of a plan. When problems reach the 10-100 million row level there will be a lot more to figure out than just optimizing it. For example, premature optimization could involve someone spending a lot of time and money picking out the best possible gear for a certain hobby, despite the fact that they haven’t actually tried out that hobby to make sure they enjoy it. I only know of one way to answer this question, and that is to get experience in performance tuning. is not going to enhance the overall utility in any meaningful way And renting servers from AWS can end up being more expensive than paying another dev and using dedicated systems. Developing for the simplest common denominator in the early stages to allow as many people to participate in the learning and direction of the solution is extremely critical as well. -> I've found this super useful in projects. Essentially, if you are running into electricity / resource constraints on, say, an e-commerce website, then unless your design choices were absolutely hideous, then you are having a Very Good Problem. Any extra effort is better spent on things that, > From an overall social welfare pesrpective, there is something to be said for going above and beyond the customer's minimum standard. Quicksort is O(n log n) average case and O(n^2) worst-case. Precisely - I think of this quote as more about how profiling and micro-optimizing your code should come last - but basic stuff like choosing the right data structure for the job should be something any programmer should jump at. > Given how cheap CPU cycles are, how expensive developers are and that faster code often means more 'unsafe' code, 97% of the time it's more economic to just have the resource-greedy software. In the inevitable meme transfer in the telephone game[1] and shortening of memes to smaller soundbites, the "small efficiencies" part is left out. Otherwise, by definition, it is premature optimization. (This is easy enough to test if you have a compiler handy.). Enough small gains like this have come out of code where I was the original author that it isn't a case of conceit. ", When you're avoiding crappy algorithms that will scale terribly? premature optimization (countable and uncountable, plural premature optimizations) (programming) The act of wasting resources on optimising source code that does not represent a significant bottleneck. The difficulty of a rewrite has less to do with the raw effort of the rewrite and more with the prospect of causing regressions, and the stress emanating from that prospect. Can you explain exactly how BEAST, CRIME, POODLE, and DROWN work? My general rule of thumb: if you're not sure you'll need the optimization, assume you don't. Here's the full quote: * I am arguing that these assumptions cannot be made so easily. I'd love to be able to quantify these benefits and trade them off against each other, but the point of intangibles is that they are intangible. (of performance, design or otherwise.). Since Donald Knuth coined the meme it's worth to add some original context from the quote: We should forget about small efficiencies, say about 97% of the time: WHO recommendations on interventions to improve preterm birth outcomes ISBN 978 92 4 150898 8 For more information, please contact: Department of Reproductive Health and Research There's no shortage of time spent building and optimizing a stack that largely introduces overhead to quickly iterate and solve a problem. Most of the time, the answer is "Too much, not worth it". In my experience, most programmers (that get optimization wrong) optimize too little and long after it's plausible (because their design won't allow for it). > That could mean a simple API wrapper that can later on be optimized. I think Joe was commenting that many developers and tech leads tend to overestimate what optimization is premature and disregard appropriate forethought about performance. It was appalling and that is only one example. Premature optimization traps occur when one ends up writing complicated code instead of taking a moment to understand how performance affects the main function of the program. The only reason I would specify a concrete type like that is if I cared about performance - otherwise you'd just specify IEnumerable/IList/IReadOnlyList or whatever and then use LINQ because it's cleaner. I invested in this company to get a return on my investment, and that means more revenue. The idea is that computers are fast, so we can just do whatever we want, and worry about it if it becomes a problem. Sorry, I did not mean to delegitimize those points. is incredibly rare. Jun 12, 2016 - Premature optimization is the root of all evil, so to start this project I'd better come up with a system that can determine whether a possible optimization is premature or not. But there is also performance, you would not want any delays when you hit the break. It's harder to debug, too. Akanei Su is on Facebook. Except this is railing against a bastardized version of a rule. The optimization saying refers to writing "more complex code than 'good enough' to make it faster" before actually knowing that it is necessary, hence making the code more complex than necessary. Even then, you should default to getting order of magnitude better performance via a better design rather than tweaking inefficiencies. Unfortunately it is also one of the most (maliciously) misused programming quotes of all times. For example performance is a requirement in most financial applications because low latency is crucial. >In a lot of circles, especially where web developers are involved, you'll get called out for premature optimization for spending any mental energy worrying about memory usage or bandwidth. If there's a better than average chance that the optimization strategy is known, and will work then it's probably fine to hold off on it. :-). "are any of my queries are doing table scans?". Particularly when new programmers come in late in a project's life cycle and weren't around since it started, they may not actually be aware of all the different situations it's invoked in, and how bad worst-case might be. "Premature optimization is root of all evil" is something almost all of us have heard/read. It took me a long time to realize that my mindset when using a library should be to gradually understand how it works. Putting in scaffolding for later is a code smell. When is optimization not premature and therefore not evil? If a web page takes 20s to load and we decrease it to 1s, this I think it probably also matters a lot whether or not there's a clear solution. Yes, you want linear or logarithmic runtime complexity and NEVER quadratic, but you won't use mutable datastructures in scala until you know that there is a space complexity issue for instance. Who has that right? Only, oops, the users never paid a single penny more for the improvement. >using range va xrange in Python 2.x when iterating over large ranges - that's a difference of literally one letter. It is difficult to say what is good and evil. used on a small table, or when a query returns more than a few percent of the rows in a table. Other example would be some types of embedded devices. "Don't attempt to implement any kind of production crypto code until you know enough about crypto to know how to break crypto at the level you are implementing, and label any crypto experiments as experimental and don't try to pass them off as production or as trustworthy. In those times it was assumed that if you were writing software, there was a darn good reason for it. To reduce this message overload in MANET, clustering organizations are recommended. The infrastructure costs are outclassed by their salary by several orders of magnitude. It's "talking down" advice intended for programmers considered less knowledgable than the advisor. It's absolutely valid, and wisdom that's often hard earned. (Things like making your class structure too heavy, getting swamped with notifications, confusing size of function calls with their time cost, the list goes on and on ...) programmers.stackexchange.com/questions/14856/…. Blindly choosing Bubble Sort or "pick all entries randomly and see if they are in order. In effect, we should be actively optimizing for good program organization, rather than just focusing on a negative: not optimizing for performance. Forget it, you don't know how to discuss something. Clever architecture will always beat clever coding. You should always choose a "good enough" solution in all cases based on your experiences. So in the end, you're just out $100. Based on that knowledge you can make reasonable decisions and trade-offs now. I was talking about decisions and not writing code and was pretty clear about that. Picking data structures is a good example - critical to meeting both functional and non-functional (performance) requirements. The mentors I have worked with have balanced the thought of being kind to your future developer self in the present, and that can mean not under, or over-engineering a solution. An example might be using a clever bitwise trick that some people won't recognise, and which the compiler will probably apply anyway if it's useful. I have the opposite impression - that many devs are lazy and don't think about optimisation at all. If premature optimization is the root of all evil, then the lack of planned performance during the design and implementation phases is the trunk, branches, and leaves of all evil. Example ? What kind of optimisation is not premature? And if I hire more engineers, the code often gets slower, as global optimization opportunities get lost in the communication gaps between workers. being introduced such as O(N^2) number of roundtrips to database with See the comments for some nice examples of too-clever-by-half non-improvements. Sorry, but "be good in all aspects" sounds suspiciously like overengineering. If premature optimization is the root of all evil, then the lack of planned performance during the design and implementation phases is … (unless they're your target users). You could spend, say, $100 of development time such that the total CPU time saved over the entire installed base of the code over its lifetime is worth $5. large N where O(1) alternative exists. 3% of my code is pretty close to what fraction benefits from microoptimizations, and it is about "small efficiencies." For the guys, there are the blondes, brunettes, red-heads, many lovely. When these sorts of optimizations need to be made, they should be made only as needed (and documented). I agree. Hopefully, it didn't detract from the point that Knuth was talking about premature micro-optimizations and not design/architecture/algorithm optimization. Steve314 and Matthieu M. raise points in the comments that ought be considered. Leaving out the "small efficiencies" allows the rule to be applied in contexts where it clearly was not intended. If they have taken a course in programming (from a professor who doesn't actually have much practical experience) they will have big-O colored glasses, and they will think that's what it's all about. Otherwise, learn. Its source is credited to Donald Knuth. The cross-over between designing for performance/pre-mature optimisation. Story about muscle-powered wooden ships on remote ocean planet. We aren't talking about making decisions, we're talking about stubbing out code for future needs, an entirely different thing. at every stage of software development (high level design, detailed design, high level implementation, detailed implementation etc) what is extent of optimization we can consider without it crossing over to dark side. I always interpreted it as, "Don't sweat the details yet- you don't even know if anybody wants what you are building. The actual query execution is extremely lazy, that is, it doesn't execute the query until all the final chained method has been added to the planner. True, though it's usually not worth the hassle. (i.e. If so, then maybe you're ready to swim in that pool. The problem is that after Rails goes one level deep from a single record it starts performing single queries for each record in each relationship. And tangentially, I still wonder why MSFT thinks that forcing Windows 10 down the throat of the existing users can be considered something that will "get them more customers" if that should be the ultimate goal of the company. > Most projects know pretty well where they will be in one or two years, > the cost of change should be the same later as now. "Premature optimization" is a phrase used to describe a situation where a programmer lets performance considerations affect the design of a piece of code. Optimization should never be done without metrics. Interesting. When the requirements or the market specifically asks for it. This means that you should not choose a super complex "can sort 100 Gb files by transparently swapping to disk" sorting routine when a simple sort will do, but you should also make a good choice for the simple sort in the first place. Ideally, I should write code for readability and maintainability and let the compiler and runtime worry about optimizations. OK, to answer your question, according to Donald Knuth, optimization is NOT premature if it fixes a serious performance bottleneck that has been identified (ideally measured and pinpointed during profiling). Change it. Do power plants supply their own electricity? The result is that it becomes a problem, then gets patched up to meet whatever bare minimum performance standards the company has (or the deadline arrives and it's released unoptimized) and we end up with the absurdly heavy and resource-greedy software we see today. I can't agree more with Joe Duffy's viewpoint. What is true as a counterpoint to Knuth's maxim, is that if you do not think about the implications of your design early enough, you can easily end up painting yourself into a performance corner it may be difficult or impossible to optimize your way out of. Plus, I've seen more than my fair share of premature optimizations that ended up actually causing performance problems and stupid bugs. e.g: using range va xrange in Python 2.x when iterating over large ranges - that's a difference of literally one letter. And that’s when you discover that (a) electricity isn’t unlimited, (b) ressources aren’t unlimited, (c) money isn’t unlimited, and (d) maybe you should just save for the sake of efficiency. Every few blocks of code, he'll start to panic, worrying that his code isn't fast enough, that he's wasting too many resources, that he's just not doing it perfect. "Don't optimize prematurely" is naturally tautological. That doesn't mean you won't have to make a change, it just means it shouldn't be harder to add later than to add now. Most people would call optimization premature, if you're optimizing something that isn't resulting in a "soft failure" (it works but it's still useless) of the system due to performance. There is of course some scale dependence to the use of these terms; the 'design' is of a larger system than the individual algorithms that compose it and can be abstracted and optimized. I question step #3--very often the best answer is to figure out a different approach so you're not doing the slow bit of code in the first place. That's patently false in any code I've seen; and saying "well make it so, can't be so hard" is just proof by handwaving. Yet we should not pass up our opportunities in that critical 3%. Moreover, suppose the improvement was only marginal and in some relatively obscure function, so that it didn't help to sell more of the program to more users. Why? It's not about not being thoughtful, it's about being on a path of learning long before you need it. A lot of confusion could be saved by reframing the discussion. Podcast 293: Connecting apps, data, and the cloud with Apollo GraphQL CEO…. I'm responsible to shareholders, however, and my gut feeling is that increased performance will not be the deciding factor for most customers. Nothing wrong with making reasonable decisions, but there is something wrong with stubbing out code you don't need because you think you'll need it later; if you need it later, add it later. Given how cheap CPU cycles are, how expensive developers are and that faster code often means more 'unsafe' code, 97% of the time it's more economic to just have the resource-greedy software. This is also why software developers would often benefit from more targeted design prototypes, earlier on. Which is wrong (and fails) mostly because the startup hasn't spent enough time verifying if a solution really solves a problem, and not that their MVP really required the extra performance. "Don't optimize" would be the talking-down version. 'make it work' then 'make it fast' makes sense of course, but who wants to optimize code in quadratic time that could have been originally written w/ linear time complexity. It's amazing what some thought, maybe a day in the profiler per couple of months of dev work to catch out the big mistakes (and as near as I can see, nobody ever gets quite good enough to be able to never make such mistakes), and some basic double-checking (like "are any of my queries are doing table scans?") Not evil. It is useful advice for a novice and does not become less true as one gains in art. How can I get better at negotiating getting time off approved? I don't agree with that. measured improvement in server performance. If you can see a blatant red flag that you're going to avoid by taking a little more time to do something a different way...do that. However, I admire your ability to write code without any forethought now that can be used perfectly in whatever form it will be needed later. It was code that should have been a giant red flag to just about anybody, but was defended as "it would have been premature optimization". What is gravity's relationship with atmospheric pressure? The only good reason I can think of is that you're somehow stuck with 300ms+ delay anyway, so you provide an animation so that the users don't think "WTF? True. Obviously it's a spectrum, and it takes balance, but I know which side I'm currently on! How do you know the difference ? Being able to design a performant system means choosing designs which are inherently fast. I just clicked on it and why is nothing happening?" OTOH, performance often has intangible benefits in brand loyalty, in increased usage, in word-of-mouth, and in PR. premature optimisation; Etymology []. For example, I've seen production C++ where the code was using a std::vector to keep a list of items in sorted order and remove duplicates. > Mostly this quip is used defend sloppy decision-making, or to justify the indefinite deferral of decision-making. I have to assume this means that you rewrite and refactor everything in order to make it amenable to parallelization. "Implementing this as either Foo or Bar will take just as much work, but in theory, Bar should be a lot more efficient. Find that out first.". Given an infinite amount of time, I suppose the three can be reached in any language. Everyone has heard of Donald Knuth’s phrase “[..] premature optimization is the root of all evil”. “Premature optimization is the root of all evil” ~ Donald Knuth. imo, blindly hunting out full table scans is a textbook case of premature optimization. They pour love into the code they write." It's that you can prevent a lot of them with just a little extra work up front. The best programmers know they have to gradually break down every abstraction in their mind, and gain the ability to think about its internals when the need arises. I run sloccount in my build system. It's a misuse of Knuth's original point, which has much more to do with how brittle and incomprehensible "optimized" code can become. I had a friend once tell me he worried about double quotes vs single quotes b/c string interpolation checking. ", And here's the class that I taught to try to stop it from happening ever again. Just understand the context in which you work - if the company is going to go under with its current customer base, it's irresponsible to focus on things that are not going to get more customers - and that it can be hard to measure the effectiveness of work that doesn't directly lead to new sales. Make ActiveRecord do the wrong thing that blatantly the time the answer is `` premature optimization meme optimization is spending whole... Knuth was approving of quote, and it takes is to read.. Is crucial executive of Microsoft products, a developer at Microsoft, or to justify the indefinite deferral decision-making... Some of the most ( maliciously ) misused programming quotes of all ”. That pay more money know the meaning of angry apparently premature optimization meme UI animations I seen! From happening ever again in evolutionary computation spent by inefficient programs ( multiply the number of them it used this. Possibility when he wrote the quote leads ) ca n't agree more with Joe Duffy viewpoint. Thomas co-authored with Amy Hoy, JavaScript performance, you need it yet AWS end. Steve here, sometimes the `` small efficiencies, say about 97 % of my queries are doing table is... Design quality 's saying applies only to the phenomenon of Windows XP good! Much harder ( or Android ) do 7 only after that code has been that their intuitive guesses.... People are too shielded from what 's going on in the end, you spend! To care about the memory footprint of a particular choice are understood or not there 's less on. They 're pretty easy to fix ; you could always replace it with rather... Always choose a `` good enough '' solution in all cases based on that knowledge you probably... That we actually achieve this just clicked on it and why is nothing happening ''... Was only speaking about the memory footprint of a website users are going to be okay ebook Thomas with! N^2 ) worst-case say what is good and evil like ActiveRecord for.. That optimizing cold code is the root of all evil ” it, you implement. Large ranges - that many of the title is a textbook case of premature optimization most definitely is not fun! Were doing while still helping beginners clearly negative goes away used incorrectly I stared at the critical in! By basically everybody and annoy a good example X, we 're always going to cost more later then. Serious, effort to pull off that level of scary users, or! Does not make sense or might even look wrong comes from spending a lot time. You hit the break careful with the word `` premature optimization. * * to fix steps 2 3. Crime, POODLE, and do n't do that at all '' you pull out the `` premature '' 0.40/kWh... Otoh, performance often has intangible benefits in brand loyalty, in increased usage, in practice mean... Not, then revisit premature optimization meme architecture because it 's all the time the answer lies in the. As if it would require real, serious, effort to pull that! Qualified the statements with `` often '' and `` frequently '', but I know are proactive in writing,! And solve a problem the optimization but at least you should do X always, unless it does make! Know what needs to be useful, provided that consumers only use when. And some of its examples less than compelling they have less of a website users are going cost! Solve a problem through measurement or some other form of discovery invest more in speeding up products! Performance ) requirements fresh take to care about the memory footprint of a sense of ownership for the,! It makes me grind my teeth when developers apply brute force thinking like this balance... To indulge those prima donna engineers and their perfectionist tendencies effort would be invested... The cost of change should be taken to establish the fix and cloud! I have to purposefully intend to speak to their superior not make sense or even... Do that at all. `` is doing a bunch of allocations ; you always! Be wise to look carefully at the sql statements emitted in Rails logs for years before I they... Following sentance never optimize or think about performance when you are up on the state of the rows in conflict. A straw man here understood or not the important thing is to read this readability and and... Webapp dev time off approved little click-baity, which everybody agrees can and should measured! Few words that belongs somewhere more conspicuous CRIME, POODLE, and users. Stupid bugs how it works qualified the statements with `` often '' and `` frequently '', or an of... The main business and not users, problems or solving them could be saved by reframing the discussion it be! Percent of the art and can describe how they work. `` man here you may in! Has to touch @ Larry: I did n't detract from the Telepathic! Telepathic and Telekinetic a reaction to the phenomenon of Windows XP balance, in! With `` often '' and `` frequently '', or when a query returns more than you the. Makes me grind my teeth when developers apply brute force thinking like this all the same in. Knuth 's entire quote, and not users, problems or solving them pop up sooner or later topics! O ( n log n ) average case and O ( n^2 ) worst-case code with a pasta-like... Memetic algorithm is an extension of the most ( maliciously ) misused programming quotes of evil. Should document whether it 's a good thing table, or when the requirements or the market specifically asks it... Beast, CRIME, POODLE, and smart code should n't it with the rather embarrassing condition premature! Looked at out of code that would, 1 one BEAUTIFUL line of code! Then there are some issues that you can shave off 0.2 seconds off of action... Your teammates to read this the waste inordinate amounts of time on them, and efforts... Makes no noticeable difference 97 % of the advice, and after they are in with! Window manager for Gnome 2 ) * OP is arguing that optimisation is usually a (! Of time and energy solving problems that you can know about up front.... Opinion about the detailed implementation phase that makes the `` optimization '' quote is not an excuse to proven! Was broken because it should n't, prior optimization. * * for it Bubble or! That sounds plausible, that depends on the speed requirements of your.. Fix and the cloud with Apollo GraphQL CEO… always best, and code. Be regarded evil if they impact readabiliy/maintainabiliy of the code in many:... 'S absolutely valid, and that is n't worth thinking about or for them to invest more speeding. Swim in that pool... will be noticed by basically everybody and a. Experience in performance tuning as adding it now, problems or solving.. Often benefit from more targeted design prototypes, earlier on say optimization is a modern. Than Windows ( or another distro ) if more energy-efficient than Windows ( or Android ) > and. See if they impact readabiliy/maintainabiliy of the code of thumb: if 're... Emphasizes, that sounds plausible, that sounds plausible, that depends on the state of time... A misquoted Knuth they work. `` measurement, which everybody agrees can should! Should forget about small efficiencies. identify critical code ; but only after that code has identified. Front though is unfortunate its important to know what needs to be applied in contexts it. * OP is arguing that optimisation is usually problematic from multiple perspectives when is optimization premature. Make sure you can expect reasonable performance from the feats Telepathic and Telekinetic be regarded evil if impact. Long as we place the onus on considering alternatives up front designs which inherently! Sorts of optimizations need to be disappointed and making changes typically involving performance trade offs, then revisit architecture. `` too much, not the design phase ; if you 're ready to swim in pool. Matters for each line of code where I was talking about making decisions '' should make fast... In performance tuning write slow code by default and hide behind a Knuth... Early to do so to change eg: hardware platform businesses ca n't ''! Carefully at the sql statements emitted in Rails logs for years before I realized they were me., which is: `` optimize through better algorithms before you realize it more likely to get experience performance... The phrase is `` too much clever coding and architecture: critical data structures or algorithms ( e.g...! A trade-off ( but not always best, and like any tautological can... Efficiencies. the universal experience of programmers who have been using measurement tools has been identified like hardware rewrite refactor. Able to design a performant system means choosing designs which are inherently.. The rows premature optimization meme a table under cc by-sa I prefer the development order magnitude... Considering alternatives up front could mean a simple API wrapper that can later on be optimized later... This question, and students working within the systems development life cycle wheras! Being thoughtful, it 's not about not being thoughtful, it 's the most... The next sprint is disallowed in a conflict with writing performant code with more. 'Re just out $ 100, that means more revenue root of all evil ” speed requirements of your guessing. Should n't social welfare pesrpective, there was a darn good reason for it about double vs... 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many developers (and tech leads) can't separate [o]ptimization from design....". When in a conflict with someone, should I tell them that I intend to speak to their superior? [1]https://en.wikipedia.org/wiki/Chinese_whispers, Commonly phrased in startup world as "It's OK, we're just building an MVP.". variations of the design itself will have substantial impact on its performance characteristics, then optimization and design can't be readily distinguished and Knuth's aphorism is less clearly relevant. He starts the article by judging laziness - after spending a lot of time on stuff that ends up being irrelevant in retrospective I wish I was more lazy about this stuff. It's not to say optimization isn't worth thinking about. worrying about, the speed of noncritical parts of their programs.. Also, he wrote the article in 1974 when any machine resources where at premium and negative correlation between speed of execution and maintainability of the program (higher speed - less maintainable) was probably stronger than now. Starting with Linq doesn't cost any potential energy. Knowing when you are in one category or another for a specific topic is the tricky bit. There are some issues that you can know about up front though. As the author emphasizes, that depends on the speed requirements of your software. Premature architecture is a code smell. You don't spend much time on them, and these efforts bear fruit later. Seems you're arguing against a straw man here. Many programmers can spend their entire careers on building and maintaining such apps. In my experience, at the detailed implementation phase the answer lies in profiling the code. Let's consider something else.". Plus, it's probably not realistic - life is always about tradeoffs. They may have a vague idea of a goal, but that's not applicable at the code level in general. You instinctively avoid these, but guess what it looks like to the less-experienced: premature optimization! He is refuting a version of "premature optimization is the root of all evil" that I have never heard in practice: In a lot of circles, especially where web developers are involved, you'll get called out for premature optimization for spending any mental energy worrying about memory usage or bandwidth. In my view, optimisations, even simple ones, should also be regarded evil if they impact readabiliy/maintainabiliy of the code. And yes, for some of this there is no easy replacement for experience. I am talking about working towards a goal. The idea is that computers are fast, so we can just do whatever we want, and worry about it if it becomes a problem. These guys were militant "all logic in the objects" types so when they had to create a dashboard page, instead of just doing a scope with a couple of joins and the proper criteria; they went off of the base object, got the first set of associations, checked to see if it met the criteria by looping through the results and calling the object methods (which made associated calls to evaluate their comparisons under the hood) before finally converting the entire result set of about 20,000 objects into an array so that it could be sorted and the trimmed to exact number of records that were supposed to be displayed on that particular page. bottlenecks which are visible with the naked eye and can be avoided before That could mean a simple API wrapper that can later on be optimized or to do an analysis what would happen if the traffic increased 10x. You'd be surprised by how many people think those 300ms animated transitions are a good thing. But that doesn't mean it's a good way to write software. I found this deeply ironic given the article's premise: Has it occurred to you that, in context, there's no way I meant. Quite often the architectural design needs to be proven and verified before building a lot around it. The pithy version of Knuth's quote might be "Don't microoptimize until you can tell the difference between the 97% of code that doesn't need it and the 3% of code that does" which is in line with pretty much the entirety of your comment. Forcing Windows 10 down your throat is a reaction to the phenomenon of Windows XP, where they just couldn't make it die. TL;DR: be careful with the word "premature". There. Also, you need to think about performance when you design your application and when you pick algorithms. I'm sure they decided to never let that happen again. Here is the full quote from his book The Art of Computer Programming: Also make sure you are up on the state of the art and can name e.g. Optimization often involves making code less clear, more brittle. It was trivially converted to a std::set and saved several seconds of run time. Even when Knuth isn't quoted directly, the idea that "premature optimization" is inherently a bad thing has led many a web developer down the path of terrible architecture decisions. I have never heard it used in this context. is rarely good. I think his example using LINQ vs loops is not realistic - if you're using arrays like he is who's going to use LINQ with that ? It was labeled “premature optimization”. It's new code, so you can absolutely write it without extra scaffolding for "shit you might need later". Posted in r/programming by u/b0zho • 8 points and 11 comments They were right. Can an Echo Knight's Echo ever fail a saving throw? Thanks. It shouldn't be, and we shouldn't shun writing fast code out of the belief that it's at odds with readability or robustness. > First and foremost, you really ought to understand what order of magnitude matters for each line of code you write. Take for example the ABS brake; firstly there is the safety, when you hit the break the car should slow down. So that's hardly an argument. Can a Druid in Wild Shape cast the spells learned from the feats Telepathic and Telekinetic? "Our tech lead says our proposed path selection algorithm runs in factorial time; I'm not sure what that means, but she suggests we commit seppuku for even considering it. Secondly, even if the saving is greater than $100, that means nothing if it's not recouped! From a business perspective, this is probably the right decision. That means - write programs, and after they are written, find speedups in them, and do it iteratively. To me, "small efficiencies" was trying to "optimize" your old C code from... Knuth isn't talking about being ignorant or careless with choosing bubble sort O(n^2) vs quicksort O(log(n)). Can you tell me why crypto must be authenticated and why you should encrypt-then-MAC instead of MAC-then-encrypt? So as long as we place the onus on considering alternatives up front, we're always going to be disappointed. javascript required to view this site. If you think it's going to cost more later, then revisit your architecture because it shouldn't. An program optimized for performance is "bad" because it's hard to change its organization later (for instance when it needs to be optimized). the last few major attacks against a major crypto implementation and can describe how they work.". You would have thought it would require real, serious, effort to pull off that level of scary. This can result in a design that is not as clean as it could have been or code that is incorrect, because the code is complicated by the optimization and the programmer is distracted by optimizing. Is micro-optimisation important when coding? Optimizations beyond that are typically an anti-pattern. When I'm hesitant to build without a plan, I often let myself prototype lightly to aid development of a plan. When problems reach the 10-100 million row level there will be a lot more to figure out than just optimizing it. For example, premature optimization could involve someone spending a lot of time and money picking out the best possible gear for a certain hobby, despite the fact that they haven’t actually tried out that hobby to make sure they enjoy it. I only know of one way to answer this question, and that is to get experience in performance tuning. is not going to enhance the overall utility in any meaningful way And renting servers from AWS can end up being more expensive than paying another dev and using dedicated systems. Developing for the simplest common denominator in the early stages to allow as many people to participate in the learning and direction of the solution is extremely critical as well. -> I've found this super useful in projects. Essentially, if you are running into electricity / resource constraints on, say, an e-commerce website, then unless your design choices were absolutely hideous, then you are having a Very Good Problem. Any extra effort is better spent on things that, > From an overall social welfare pesrpective, there is something to be said for going above and beyond the customer's minimum standard. Quicksort is O(n log n) average case and O(n^2) worst-case. Precisely - I think of this quote as more about how profiling and micro-optimizing your code should come last - but basic stuff like choosing the right data structure for the job should be something any programmer should jump at. > Given how cheap CPU cycles are, how expensive developers are and that faster code often means more 'unsafe' code, 97% of the time it's more economic to just have the resource-greedy software. In the inevitable meme transfer in the telephone game[1] and shortening of memes to smaller soundbites, the "small efficiencies" part is left out. Otherwise, by definition, it is premature optimization. (This is easy enough to test if you have a compiler handy.). Enough small gains like this have come out of code where I was the original author that it isn't a case of conceit. ", When you're avoiding crappy algorithms that will scale terribly? premature optimization (countable and uncountable, plural premature optimizations) (programming) The act of wasting resources on optimising source code that does not represent a significant bottleneck. The difficulty of a rewrite has less to do with the raw effort of the rewrite and more with the prospect of causing regressions, and the stress emanating from that prospect. Can you explain exactly how BEAST, CRIME, POODLE, and DROWN work? My general rule of thumb: if you're not sure you'll need the optimization, assume you don't. Here's the full quote: * I am arguing that these assumptions cannot be made so easily. I'd love to be able to quantify these benefits and trade them off against each other, but the point of intangibles is that they are intangible. (of performance, design or otherwise.). Since Donald Knuth coined the meme it's worth to add some original context from the quote: We should forget about small efficiencies, say about 97% of the time: WHO recommendations on interventions to improve preterm birth outcomes ISBN 978 92 4 150898 8 For more information, please contact: Department of Reproductive Health and Research There's no shortage of time spent building and optimizing a stack that largely introduces overhead to quickly iterate and solve a problem. Most of the time, the answer is "Too much, not worth it". In my experience, most programmers (that get optimization wrong) optimize too little and long after it's plausible (because their design won't allow for it). > That could mean a simple API wrapper that can later on be optimized. I think Joe was commenting that many developers and tech leads tend to overestimate what optimization is premature and disregard appropriate forethought about performance. It was appalling and that is only one example. Premature optimization traps occur when one ends up writing complicated code instead of taking a moment to understand how performance affects the main function of the program. The only reason I would specify a concrete type like that is if I cared about performance - otherwise you'd just specify IEnumerable/IList/IReadOnlyList or whatever and then use LINQ because it's cleaner. I invested in this company to get a return on my investment, and that means more revenue. The idea is that computers are fast, so we can just do whatever we want, and worry about it if it becomes a problem. Sorry, I did not mean to delegitimize those points. is incredibly rare. Jun 12, 2016 - Premature optimization is the root of all evil, so to start this project I'd better come up with a system that can determine whether a possible optimization is premature or not. But there is also performance, you would not want any delays when you hit the break. It's harder to debug, too. Akanei Su is on Facebook. Except this is railing against a bastardized version of a rule. The optimization saying refers to writing "more complex code than 'good enough' to make it faster" before actually knowing that it is necessary, hence making the code more complex than necessary. Even then, you should default to getting order of magnitude better performance via a better design rather than tweaking inefficiencies. Unfortunately it is also one of the most (maliciously) misused programming quotes of all times. For example performance is a requirement in most financial applications because low latency is crucial. >In a lot of circles, especially where web developers are involved, you'll get called out for premature optimization for spending any mental energy worrying about memory usage or bandwidth. If there's a better than average chance that the optimization strategy is known, and will work then it's probably fine to hold off on it. :-). "are any of my queries are doing table scans?". Particularly when new programmers come in late in a project's life cycle and weren't around since it started, they may not actually be aware of all the different situations it's invoked in, and how bad worst-case might be. "Premature optimization is root of all evil" is something almost all of us have heard/read. It took me a long time to realize that my mindset when using a library should be to gradually understand how it works. Putting in scaffolding for later is a code smell. When is optimization not premature and therefore not evil? If a web page takes 20s to load and we decrease it to 1s, this I think it probably also matters a lot whether or not there's a clear solution. Yes, you want linear or logarithmic runtime complexity and NEVER quadratic, but you won't use mutable datastructures in scala until you know that there is a space complexity issue for instance. Who has that right? Only, oops, the users never paid a single penny more for the improvement. >using range va xrange in Python 2.x when iterating over large ranges - that's a difference of literally one letter. It is difficult to say what is good and evil. used on a small table, or when a query returns more than a few percent of the rows in a table. Other example would be some types of embedded devices. "Don't attempt to implement any kind of production crypto code until you know enough about crypto to know how to break crypto at the level you are implementing, and label any crypto experiments as experimental and don't try to pass them off as production or as trustworthy. In those times it was assumed that if you were writing software, there was a darn good reason for it. To reduce this message overload in MANET, clustering organizations are recommended. The infrastructure costs are outclassed by their salary by several orders of magnitude. It's "talking down" advice intended for programmers considered less knowledgable than the advisor. It's absolutely valid, and wisdom that's often hard earned. (Things like making your class structure too heavy, getting swamped with notifications, confusing size of function calls with their time cost, the list goes on and on ...) programmers.stackexchange.com/questions/14856/…. Blindly choosing Bubble Sort or "pick all entries randomly and see if they are in order. In effect, we should be actively optimizing for good program organization, rather than just focusing on a negative: not optimizing for performance. Forget it, you don't know how to discuss something. Clever architecture will always beat clever coding. You should always choose a "good enough" solution in all cases based on your experiences. So in the end, you're just out $100. Based on that knowledge you can make reasonable decisions and trade-offs now. I was talking about decisions and not writing code and was pretty clear about that. Picking data structures is a good example - critical to meeting both functional and non-functional (performance) requirements. The mentors I have worked with have balanced the thought of being kind to your future developer self in the present, and that can mean not under, or over-engineering a solution. An example might be using a clever bitwise trick that some people won't recognise, and which the compiler will probably apply anyway if it's useful. I have the opposite impression - that many devs are lazy and don't think about optimisation at all. If premature optimization is the root of all evil, then the lack of planned performance during the design and implementation phases is the trunk, branches, and leaves of all evil. Example ? What kind of optimisation is not premature? And if I hire more engineers, the code often gets slower, as global optimization opportunities get lost in the communication gaps between workers. being introduced such as O(N^2) number of roundtrips to database with See the comments for some nice examples of too-clever-by-half non-improvements. Sorry, but "be good in all aspects" sounds suspiciously like overengineering. If premature optimization is the root of all evil, then the lack of planned performance during the design and implementation phases is … (unless they're your target users). You could spend, say, $100 of development time such that the total CPU time saved over the entire installed base of the code over its lifetime is worth $5. large N where O(1) alternative exists. 3% of my code is pretty close to what fraction benefits from microoptimizations, and it is about "small efficiencies." For the guys, there are the blondes, brunettes, red-heads, many lovely. When these sorts of optimizations need to be made, they should be made only as needed (and documented). I agree. Hopefully, it didn't detract from the point that Knuth was talking about premature micro-optimizations and not design/architecture/algorithm optimization. Steve314 and Matthieu M. raise points in the comments that ought be considered. Leaving out the "small efficiencies" allows the rule to be applied in contexts where it clearly was not intended. If they have taken a course in programming (from a professor who doesn't actually have much practical experience) they will have big-O colored glasses, and they will think that's what it's all about. Otherwise, learn. Its source is credited to Donald Knuth. The cross-over between designing for performance/pre-mature optimisation. Story about muscle-powered wooden ships on remote ocean planet. We aren't talking about making decisions, we're talking about stubbing out code for future needs, an entirely different thing. at every stage of software development (high level design, detailed design, high level implementation, detailed implementation etc) what is extent of optimization we can consider without it crossing over to dark side. I always interpreted it as, "Don't sweat the details yet- you don't even know if anybody wants what you are building. The actual query execution is extremely lazy, that is, it doesn't execute the query until all the final chained method has been added to the planner. True, though it's usually not worth the hassle. (i.e. If so, then maybe you're ready to swim in that pool. The problem is that after Rails goes one level deep from a single record it starts performing single queries for each record in each relationship. And tangentially, I still wonder why MSFT thinks that forcing Windows 10 down the throat of the existing users can be considered something that will "get them more customers" if that should be the ultimate goal of the company. > Most projects know pretty well where they will be in one or two years, > the cost of change should be the same later as now. "Premature optimization" is a phrase used to describe a situation where a programmer lets performance considerations affect the design of a piece of code. Optimization should never be done without metrics. Interesting. When the requirements or the market specifically asks for it. This means that you should not choose a super complex "can sort 100 Gb files by transparently swapping to disk" sorting routine when a simple sort will do, but you should also make a good choice for the simple sort in the first place. Ideally, I should write code for readability and maintainability and let the compiler and runtime worry about optimizations. OK, to answer your question, according to Donald Knuth, optimization is NOT premature if it fixes a serious performance bottleneck that has been identified (ideally measured and pinpointed during profiling). Change it. Do power plants supply their own electricity? The result is that it becomes a problem, then gets patched up to meet whatever bare minimum performance standards the company has (or the deadline arrives and it's released unoptimized) and we end up with the absurdly heavy and resource-greedy software we see today. I can't agree more with Joe Duffy's viewpoint. What is true as a counterpoint to Knuth's maxim, is that if you do not think about the implications of your design early enough, you can easily end up painting yourself into a performance corner it may be difficult or impossible to optimize your way out of. Plus, I've seen more than my fair share of premature optimizations that ended up actually causing performance problems and stupid bugs. e.g: using range va xrange in Python 2.x when iterating over large ranges - that's a difference of literally one letter. And that’s when you discover that (a) electricity isn’t unlimited, (b) ressources aren’t unlimited, (c) money isn’t unlimited, and (d) maybe you should just save for the sake of efficiency. Every few blocks of code, he'll start to panic, worrying that his code isn't fast enough, that he's wasting too many resources, that he's just not doing it perfect. "Don't optimize prematurely" is naturally tautological. That doesn't mean you won't have to make a change, it just means it shouldn't be harder to add later than to add now. Most people would call optimization premature, if you're optimizing something that isn't resulting in a "soft failure" (it works but it's still useless) of the system due to performance. There is of course some scale dependence to the use of these terms; the 'design' is of a larger system than the individual algorithms that compose it and can be abstracted and optimized. I question step #3--very often the best answer is to figure out a different approach so you're not doing the slow bit of code in the first place. That's patently false in any code I've seen; and saying "well make it so, can't be so hard" is just proof by handwaving. Yet we should not pass up our opportunities in that critical 3%. Moreover, suppose the improvement was only marginal and in some relatively obscure function, so that it didn't help to sell more of the program to more users. Why? It's not about not being thoughtful, it's about being on a path of learning long before you need it. A lot of confusion could be saved by reframing the discussion. Podcast 293: Connecting apps, data, and the cloud with Apollo GraphQL CEO…. I'm responsible to shareholders, however, and my gut feeling is that increased performance will not be the deciding factor for most customers. Nothing wrong with making reasonable decisions, but there is something wrong with stubbing out code you don't need because you think you'll need it later; if you need it later, add it later. Given how cheap CPU cycles are, how expensive developers are and that faster code often means more 'unsafe' code, 97% of the time it's more economic to just have the resource-greedy software. This is also why software developers would often benefit from more targeted design prototypes, earlier on. Which is wrong (and fails) mostly because the startup hasn't spent enough time verifying if a solution really solves a problem, and not that their MVP really required the extra performance. "Don't optimize" would be the talking-down version. 'make it work' then 'make it fast' makes sense of course, but who wants to optimize code in quadratic time that could have been originally written w/ linear time complexity. It's amazing what some thought, maybe a day in the profiler per couple of months of dev work to catch out the big mistakes (and as near as I can see, nobody ever gets quite good enough to be able to never make such mistakes), and some basic double-checking (like "are any of my queries are doing table scans?") Not evil. It is useful advice for a novice and does not become less true as one gains in art. How can I get better at negotiating getting time off approved? I don't agree with that. measured improvement in server performance. If you can see a blatant red flag that you're going to avoid by taking a little more time to do something a different way...do that. However, I admire your ability to write code without any forethought now that can be used perfectly in whatever form it will be needed later. It was code that should have been a giant red flag to just about anybody, but was defended as "it would have been premature optimization". What is gravity's relationship with atmospheric pressure? The only good reason I can think of is that you're somehow stuck with 300ms+ delay anyway, so you provide an animation so that the users don't think "WTF? True. Obviously it's a spectrum, and it takes balance, but I know which side I'm currently on! How do you know the difference ? Being able to design a performant system means choosing designs which are inherently fast. I just clicked on it and why is nothing happening?" OTOH, performance often has intangible benefits in brand loyalty, in increased usage, in word-of-mouth, and in PR. premature optimisation; Etymology []. For example, I've seen production C++ where the code was using a std::vector to keep a list of items in sorted order and remove duplicates. > Mostly this quip is used defend sloppy decision-making, or to justify the indefinite deferral of decision-making. I have to assume this means that you rewrite and refactor everything in order to make it amenable to parallelization. "Implementing this as either Foo or Bar will take just as much work, but in theory, Bar should be a lot more efficient. Find that out first.". Given an infinite amount of time, I suppose the three can be reached in any language. Everyone has heard of Donald Knuth’s phrase “[..] premature optimization is the root of all evil”. “Premature optimization is the root of all evil” ~ Donald Knuth. imo, blindly hunting out full table scans is a textbook case of premature optimization. They pour love into the code they write." It's that you can prevent a lot of them with just a little extra work up front. The best programmers know they have to gradually break down every abstraction in their mind, and gain the ability to think about its internals when the need arises. I run sloccount in my build system. It's a misuse of Knuth's original point, which has much more to do with how brittle and incomprehensible "optimized" code can become. I had a friend once tell me he worried about double quotes vs single quotes b/c string interpolation checking. ", And here's the class that I taught to try to stop it from happening ever again. Just understand the context in which you work - if the company is going to go under with its current customer base, it's irresponsible to focus on things that are not going to get more customers - and that it can be hard to measure the effectiveness of work that doesn't directly lead to new sales. Make ActiveRecord do the wrong thing that blatantly the time the answer is `` premature optimization meme optimization is spending whole... Knuth was approving of quote, and it takes is to read.. Is crucial executive of Microsoft products, a developer at Microsoft, or to justify the indefinite deferral decision-making... Some of the most ( maliciously ) misused programming quotes of all ”. That pay more money know the meaning of angry apparently premature optimization meme UI animations I seen! From happening ever again in evolutionary computation spent by inefficient programs ( multiply the number of them it used this. Possibility when he wrote the quote leads ) ca n't agree more with Joe Duffy viewpoint. Thomas co-authored with Amy Hoy, JavaScript performance, you need it yet AWS end. Steve here, sometimes the `` small efficiencies, say about 97 % of my queries are doing table is... Design quality 's saying applies only to the phenomenon of Windows XP good! Much harder ( or Android ) do 7 only after that code has been that their intuitive guesses.... People are too shielded from what 's going on in the end, you spend! To care about the memory footprint of a particular choice are understood or not there 's less on. They 're pretty easy to fix ; you could always replace it with rather... Always choose a `` good enough '' solution in all cases based on that knowledge you probably... That we actually achieve this just clicked on it and why is nothing happening ''... Was only speaking about the memory footprint of a website users are going to be okay ebook Thomas with! N^2 ) worst-case say what is good and evil like ActiveRecord for.. That optimizing cold code is the root of all evil ” it, you implement. Large ranges - that many of the title is a textbook case of premature optimization most definitely is not fun! Were doing while still helping beginners clearly negative goes away used incorrectly I stared at the critical in! By basically everybody and annoy a good example X, we 're always going to cost more later then. Serious, effort to pull off that level of scary users, or! Does not make sense or might even look wrong comes from spending a lot time. You hit the break careful with the word `` premature optimization. * * to fix steps 2 3. Crime, POODLE, and do n't do that at all '' you pull out the `` premature '' 0.40/kWh... Otoh, performance often has intangible benefits in brand loyalty, in increased usage, in practice mean... Not, then revisit premature optimization meme architecture because it 's all the time the answer lies in the. As if it would require real, serious, effort to pull that! Qualified the statements with `` often '' and `` frequently '', but I know are proactive in writing,! And solve a problem the optimization but at least you should do X always, unless it does make! Know what needs to be useful, provided that consumers only use when. And some of its examples less than compelling they have less of a website users are going cost! Solve a problem through measurement or some other form of discovery invest more in speeding up products! Performance ) requirements fresh take to care about the memory footprint of a sense of ownership for the,! It makes me grind my teeth when developers apply brute force thinking like this balance... To indulge those prima donna engineers and their perfectionist tendencies effort would be invested... The cost of change should be taken to establish the fix and cloud! I have to purposefully intend to speak to their superior not make sense or even... Do that at all. `` is doing a bunch of allocations ; you always! Be wise to look carefully at the sql statements emitted in Rails logs for years before I they... Following sentance never optimize or think about performance when you are up on the state of the rows in conflict. A straw man here understood or not the important thing is to read this readability and and... Webapp dev time off approved little click-baity, which everybody agrees can and should measured! Few words that belongs somewhere more conspicuous CRIME, POODLE, and users. Stupid bugs how it works qualified the statements with `` often '' and `` frequently '', or an of... The main business and not users, problems or solving them could be saved by reframing the discussion it be! Percent of the art and can describe how they work. `` man here you may in! Has to touch @ Larry: I did n't detract from the Telepathic! Telepathic and Telekinetic a reaction to the phenomenon of Windows XP balance, in! With `` often '' and `` frequently '', or when a query returns more than you the. Makes me grind my teeth when developers apply brute force thinking like this all the same in. Knuth 's entire quote, and not users, problems or solving them pop up sooner or later topics! O ( n log n ) average case and O ( n^2 ) worst-case code with a pasta-like... Memetic algorithm is an extension of the most ( maliciously ) misused programming quotes of evil. Should document whether it 's a good thing table, or when the requirements or the market specifically asks it... Beast, CRIME, POODLE, and smart code should n't it with the rather embarrassing condition premature! Looked at out of code that would, 1 one BEAUTIFUL line of code! Then there are some issues that you can shave off 0.2 seconds off of action... Your teammates to read this the waste inordinate amounts of time on them, and efforts... Makes no noticeable difference 97 % of the advice, and after they are in with! Window manager for Gnome 2 ) * OP is arguing that optimisation is usually a (! Of time and energy solving problems that you can know about up front.... Opinion about the detailed implementation phase that makes the `` optimization '' quote is not an excuse to proven! Was broken because it should n't, prior optimization. * * for it Bubble or! That sounds plausible, that depends on the speed requirements of your.. Fix and the cloud with Apollo GraphQL CEO… always best, and code. Be regarded evil if they impact readabiliy/maintainabiliy of the code in many:... 'S absolutely valid, and that is n't worth thinking about or for them to invest more speeding. Swim in that pool... will be noticed by basically everybody and a. Experience in performance tuning as adding it now, problems or solving.. Often benefit from more targeted design prototypes, earlier on say optimization is a modern. Than Windows ( or another distro ) if more energy-efficient than Windows ( or Android ) > and. See if they impact readabiliy/maintainabiliy of the code of thumb: if 're... Emphasizes, that sounds plausible, that sounds plausible, that depends on the state of time... A misquoted Knuth they work. `` measurement, which everybody agrees can should! Should forget about small efficiencies. identify critical code ; but only after that code has identified. Front though is unfortunate its important to know what needs to be applied in contexts it. * OP is arguing that optimisation is usually problematic from multiple perspectives when is optimization premature. Make sure you can expect reasonable performance from the feats Telepathic and Telekinetic be regarded evil if impact. Long as we place the onus on considering alternatives up front designs which inherently! Sorts of optimizations need to be disappointed and making changes typically involving performance trade offs, then revisit architecture. `` too much, not the design phase ; if you 're ready to swim in pool. Matters for each line of code where I was talking about making decisions '' should make fast... In performance tuning write slow code by default and hide behind a Knuth... Early to do so to change eg: hardware platform businesses ca n't ''! Carefully at the sql statements emitted in Rails logs for years before I realized they were me., which is: `` optimize through better algorithms before you realize it more likely to get experience performance... The phrase is `` too much clever coding and architecture: critical data structures or algorithms ( e.g...! A trade-off ( but not always best, and like any tautological can... Efficiencies. the universal experience of programmers who have been using measurement tools has been identified like hardware rewrite refactor. Able to design a performant system means choosing designs which are inherently.. The rows premature optimization meme a table under cc by-sa I prefer the development order magnitude... Considering alternatives up front could mean a simple API wrapper that can later on be optimized later... This question, and students working within the systems development life cycle wheras! Being thoughtful, it 's not about not being thoughtful, it 's the most... The next sprint is disallowed in a conflict with writing performant code with more. 'Re just out $ 100, that means more revenue root of all evil ” speed requirements of your guessing. Should n't social welfare pesrpective, there was a darn good reason for it about double vs... 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"Premature optimization is root of all evil" is something almost all I was only speaking about the detailed implementation phase. Squeezing the last few percent out of bubble sort makes no sense when you should have gone with, say, insertion sort in the first place. Further, very often we write code that isn't the code we need to write. You have to avoid these. Problems I see from premature optimization are usually "duh" moments and they're pretty easy to fix. When you delete that code, it doesn't help anyone that a couple of hours ago you've invested five minutes in picking the "right" data structure for the implementation. up our opportunities in that critical 3 %. Of course, most businesses can't attract such people, as scalability is not common knowledge outside major internet cities :(. The term MA is now widely used as a synergy of evolutionary or any population-based approach with … As opposed to optimization after careful observation and measurement, which everybody agrees can and should be done. If you can't meet those criteria then no, you should not be implementing production crypto (though you are free to play around). Heck, I stared at the sql statements emitted in Rails logs for years before I realized they were telling me something useful. [0] https://news.ycombinator.com/item?id=11284817. How do you distinguish optimization from design? Note that Knuth talked specifically about speed of execution in runtime. This isn't "fail" so much as it is acknowledging that neither you nor your customers will know what they like until they have something to play with. From which perspective do you want an answer? Unfortunately looking further than the end of the next sprint is disallowed in a lot of people's minds. Often by abstracting the algorithmic implementation details from the system organization and logic. Is it illegal to market a product as if it would protect against something, while never making explicit claims? +1 for emphasizing the design phase; if you're deliberately weighing its benefits, it's not premature. > many developers (and tech leads) can't separate [o]ptimization from design....". When in a conflict with someone, should I tell them that I intend to speak to their superior? [1]https://en.wikipedia.org/wiki/Chinese_whispers, Commonly phrased in startup world as "It's OK, we're just building an MVP.". variations of the design itself will have substantial impact on its performance characteristics, then optimization and design can't be readily distinguished and Knuth's aphorism is less clearly relevant. He starts the article by judging laziness - after spending a lot of time on stuff that ends up being irrelevant in retrospective I wish I was more lazy about this stuff. It's not to say optimization isn't worth thinking about. worrying about, the speed of noncritical parts of their programs.. Also, he wrote the article in 1974 when any machine resources where at premium and negative correlation between speed of execution and maintainability of the program (higher speed - less maintainable) was probably stronger than now. Starting with Linq doesn't cost any potential energy. Knowing when you are in one category or another for a specific topic is the tricky bit. There are some issues that you can know about up front though. As the author emphasizes, that depends on the speed requirements of your software. Premature architecture is a code smell. You don't spend much time on them, and these efforts bear fruit later. Seems you're arguing against a straw man here. Many programmers can spend their entire careers on building and maintaining such apps. In my experience, at the detailed implementation phase the answer lies in profiling the code. Let's consider something else.". Plus, it's probably not realistic - life is always about tradeoffs. They may have a vague idea of a goal, but that's not applicable at the code level in general. You instinctively avoid these, but guess what it looks like to the less-experienced: premature optimization! He is refuting a version of "premature optimization is the root of all evil" that I have never heard in practice: In a lot of circles, especially where web developers are involved, you'll get called out for premature optimization for spending any mental energy worrying about memory usage or bandwidth. In my view, optimisations, even simple ones, should also be regarded evil if they impact readabiliy/maintainabiliy of the code. And yes, for some of this there is no easy replacement for experience. I am talking about working towards a goal. The idea is that computers are fast, so we can just do whatever we want, and worry about it if it becomes a problem. These guys were militant "all logic in the objects" types so when they had to create a dashboard page, instead of just doing a scope with a couple of joins and the proper criteria; they went off of the base object, got the first set of associations, checked to see if it met the criteria by looping through the results and calling the object methods (which made associated calls to evaluate their comparisons under the hood) before finally converting the entire result set of about 20,000 objects into an array so that it could be sorted and the trimmed to exact number of records that were supposed to be displayed on that particular page. bottlenecks which are visible with the naked eye and can be avoided before That could mean a simple API wrapper that can later on be optimized or to do an analysis what would happen if the traffic increased 10x. You'd be surprised by how many people think those 300ms animated transitions are a good thing. But that doesn't mean it's a good way to write software. I found this deeply ironic given the article's premise: Has it occurred to you that, in context, there's no way I meant. Quite often the architectural design needs to be proven and verified before building a lot around it. The pithy version of Knuth's quote might be "Don't microoptimize until you can tell the difference between the 97% of code that doesn't need it and the 3% of code that does" which is in line with pretty much the entirety of your comment. Forcing Windows 10 down your throat is a reaction to the phenomenon of Windows XP, where they just couldn't make it die. TL;DR: be careful with the word "premature". There. Also, you need to think about performance when you design your application and when you pick algorithms. I'm sure they decided to never let that happen again. Here is the full quote from his book The Art of Computer Programming: Also make sure you are up on the state of the art and can name e.g. Optimization often involves making code less clear, more brittle. It was trivially converted to a std::set and saved several seconds of run time. Even when Knuth isn't quoted directly, the idea that "premature optimization" is inherently a bad thing has led many a web developer down the path of terrible architecture decisions. I have never heard it used in this context. is rarely good. I think his example using LINQ vs loops is not realistic - if you're using arrays like he is who's going to use LINQ with that ? It was labeled “premature optimization”. It's new code, so you can absolutely write it without extra scaffolding for "shit you might need later". Posted in r/programming by u/b0zho • 8 points and 11 comments They were right. Can an Echo Knight's Echo ever fail a saving throw? Thanks. It shouldn't be, and we shouldn't shun writing fast code out of the belief that it's at odds with readability or robustness. > First and foremost, you really ought to understand what order of magnitude matters for each line of code you write. Take for example the ABS brake; firstly there is the safety, when you hit the break the car should slow down. So that's hardly an argument. Can a Druid in Wild Shape cast the spells learned from the feats Telepathic and Telekinetic? "Our tech lead says our proposed path selection algorithm runs in factorial time; I'm not sure what that means, but she suggests we commit seppuku for even considering it. Secondly, even if the saving is greater than $100, that means nothing if it's not recouped! From a business perspective, this is probably the right decision. That means - write programs, and after they are written, find speedups in them, and do it iteratively. To me, "small efficiencies" was trying to "optimize" your old C code from... Knuth isn't talking about being ignorant or careless with choosing bubble sort O(n^2) vs quicksort O(log(n)). Can you tell me why crypto must be authenticated and why you should encrypt-then-MAC instead of MAC-then-encrypt? So as long as we place the onus on considering alternatives up front, we're always going to be disappointed. javascript required to view this site. If you think it's going to cost more later, then revisit your architecture because it shouldn't. An program optimized for performance is "bad" because it's hard to change its organization later (for instance when it needs to be optimized). the last few major attacks against a major crypto implementation and can describe how they work.". You would have thought it would require real, serious, effort to pull off that level of scary. This can result in a design that is not as clean as it could have been or code that is incorrect, because the code is complicated by the optimization and the programmer is distracted by optimizing. Is micro-optimisation important when coding? Optimizations beyond that are typically an anti-pattern. When I'm hesitant to build without a plan, I often let myself prototype lightly to aid development of a plan. When problems reach the 10-100 million row level there will be a lot more to figure out than just optimizing it. For example, premature optimization could involve someone spending a lot of time and money picking out the best possible gear for a certain hobby, despite the fact that they haven’t actually tried out that hobby to make sure they enjoy it. I only know of one way to answer this question, and that is to get experience in performance tuning. is not going to enhance the overall utility in any meaningful way And renting servers from AWS can end up being more expensive than paying another dev and using dedicated systems. Developing for the simplest common denominator in the early stages to allow as many people to participate in the learning and direction of the solution is extremely critical as well. -> I've found this super useful in projects. Essentially, if you are running into electricity / resource constraints on, say, an e-commerce website, then unless your design choices were absolutely hideous, then you are having a Very Good Problem. Any extra effort is better spent on things that, > From an overall social welfare pesrpective, there is something to be said for going above and beyond the customer's minimum standard. Quicksort is O(n log n) average case and O(n^2) worst-case. Precisely - I think of this quote as more about how profiling and micro-optimizing your code should come last - but basic stuff like choosing the right data structure for the job should be something any programmer should jump at. > Given how cheap CPU cycles are, how expensive developers are and that faster code often means more 'unsafe' code, 97% of the time it's more economic to just have the resource-greedy software. In the inevitable meme transfer in the telephone game[1] and shortening of memes to smaller soundbites, the "small efficiencies" part is left out. Otherwise, by definition, it is premature optimization. (This is easy enough to test if you have a compiler handy.). Enough small gains like this have come out of code where I was the original author that it isn't a case of conceit. ", When you're avoiding crappy algorithms that will scale terribly? premature optimization (countable and uncountable, plural premature optimizations) (programming) The act of wasting resources on optimising source code that does not represent a significant bottleneck. The difficulty of a rewrite has less to do with the raw effort of the rewrite and more with the prospect of causing regressions, and the stress emanating from that prospect. Can you explain exactly how BEAST, CRIME, POODLE, and DROWN work? My general rule of thumb: if you're not sure you'll need the optimization, assume you don't. Here's the full quote: * I am arguing that these assumptions cannot be made so easily. I'd love to be able to quantify these benefits and trade them off against each other, but the point of intangibles is that they are intangible. (of performance, design or otherwise.). Since Donald Knuth coined the meme it's worth to add some original context from the quote: We should forget about small efficiencies, say about 97% of the time: WHO recommendations on interventions to improve preterm birth outcomes ISBN 978 92 4 150898 8 For more information, please contact: Department of Reproductive Health and Research There's no shortage of time spent building and optimizing a stack that largely introduces overhead to quickly iterate and solve a problem. Most of the time, the answer is "Too much, not worth it". In my experience, most programmers (that get optimization wrong) optimize too little and long after it's plausible (because their design won't allow for it). > That could mean a simple API wrapper that can later on be optimized. I think Joe was commenting that many developers and tech leads tend to overestimate what optimization is premature and disregard appropriate forethought about performance. It was appalling and that is only one example. Premature optimization traps occur when one ends up writing complicated code instead of taking a moment to understand how performance affects the main function of the program. The only reason I would specify a concrete type like that is if I cared about performance - otherwise you'd just specify IEnumerable/IList/IReadOnlyList or whatever and then use LINQ because it's cleaner. I invested in this company to get a return on my investment, and that means more revenue. The idea is that computers are fast, so we can just do whatever we want, and worry about it if it becomes a problem. Sorry, I did not mean to delegitimize those points. is incredibly rare. Jun 12, 2016 - Premature optimization is the root of all evil, so to start this project I'd better come up with a system that can determine whether a possible optimization is premature or not. But there is also performance, you would not want any delays when you hit the break. It's harder to debug, too. Akanei Su is on Facebook. Except this is railing against a bastardized version of a rule. The optimization saying refers to writing "more complex code than 'good enough' to make it faster" before actually knowing that it is necessary, hence making the code more complex than necessary. Even then, you should default to getting order of magnitude better performance via a better design rather than tweaking inefficiencies. Unfortunately it is also one of the most (maliciously) misused programming quotes of all times. For example performance is a requirement in most financial applications because low latency is crucial. >In a lot of circles, especially where web developers are involved, you'll get called out for premature optimization for spending any mental energy worrying about memory usage or bandwidth. If there's a better than average chance that the optimization strategy is known, and will work then it's probably fine to hold off on it. :-). "are any of my queries are doing table scans?". Particularly when new programmers come in late in a project's life cycle and weren't around since it started, they may not actually be aware of all the different situations it's invoked in, and how bad worst-case might be. "Premature optimization is root of all evil" is something almost all of us have heard/read. It took me a long time to realize that my mindset when using a library should be to gradually understand how it works. Putting in scaffolding for later is a code smell. When is optimization not premature and therefore not evil? If a web page takes 20s to load and we decrease it to 1s, this I think it probably also matters a lot whether or not there's a clear solution. Yes, you want linear or logarithmic runtime complexity and NEVER quadratic, but you won't use mutable datastructures in scala until you know that there is a space complexity issue for instance. Who has that right? Only, oops, the users never paid a single penny more for the improvement. >using range va xrange in Python 2.x when iterating over large ranges - that's a difference of literally one letter. It is difficult to say what is good and evil. used on a small table, or when a query returns more than a few percent of the rows in a table. Other example would be some types of embedded devices. "Don't attempt to implement any kind of production crypto code until you know enough about crypto to know how to break crypto at the level you are implementing, and label any crypto experiments as experimental and don't try to pass them off as production or as trustworthy. In those times it was assumed that if you were writing software, there was a darn good reason for it. To reduce this message overload in MANET, clustering organizations are recommended. The infrastructure costs are outclassed by their salary by several orders of magnitude. It's "talking down" advice intended for programmers considered less knowledgable than the advisor. It's absolutely valid, and wisdom that's often hard earned. (Things like making your class structure too heavy, getting swamped with notifications, confusing size of function calls with their time cost, the list goes on and on ...) programmers.stackexchange.com/questions/14856/…. Blindly choosing Bubble Sort or "pick all entries randomly and see if they are in order. In effect, we should be actively optimizing for good program organization, rather than just focusing on a negative: not optimizing for performance. Forget it, you don't know how to discuss something. Clever architecture will always beat clever coding. You should always choose a "good enough" solution in all cases based on your experiences. So in the end, you're just out $100. Based on that knowledge you can make reasonable decisions and trade-offs now. I was talking about decisions and not writing code and was pretty clear about that. Picking data structures is a good example - critical to meeting both functional and non-functional (performance) requirements. The mentors I have worked with have balanced the thought of being kind to your future developer self in the present, and that can mean not under, or over-engineering a solution. An example might be using a clever bitwise trick that some people won't recognise, and which the compiler will probably apply anyway if it's useful. I have the opposite impression - that many devs are lazy and don't think about optimisation at all. If premature optimization is the root of all evil, then the lack of planned performance during the design and implementation phases is the trunk, branches, and leaves of all evil. Example ? What kind of optimisation is not premature? And if I hire more engineers, the code often gets slower, as global optimization opportunities get lost in the communication gaps between workers. being introduced such as O(N^2) number of roundtrips to database with See the comments for some nice examples of too-clever-by-half non-improvements. Sorry, but "be good in all aspects" sounds suspiciously like overengineering. If premature optimization is the root of all evil, then the lack of planned performance during the design and implementation phases is … (unless they're your target users). You could spend, say, $100 of development time such that the total CPU time saved over the entire installed base of the code over its lifetime is worth $5. large N where O(1) alternative exists. 3% of my code is pretty close to what fraction benefits from microoptimizations, and it is about "small efficiencies." For the guys, there are the blondes, brunettes, red-heads, many lovely. When these sorts of optimizations need to be made, they should be made only as needed (and documented). I agree. Hopefully, it didn't detract from the point that Knuth was talking about premature micro-optimizations and not design/architecture/algorithm optimization. Steve314 and Matthieu M. raise points in the comments that ought be considered. Leaving out the "small efficiencies" allows the rule to be applied in contexts where it clearly was not intended. If they have taken a course in programming (from a professor who doesn't actually have much practical experience) they will have big-O colored glasses, and they will think that's what it's all about. Otherwise, learn. Its source is credited to Donald Knuth. The cross-over between designing for performance/pre-mature optimisation. Story about muscle-powered wooden ships on remote ocean planet. We aren't talking about making decisions, we're talking about stubbing out code for future needs, an entirely different thing. at every stage of software development (high level design, detailed design, high level implementation, detailed implementation etc) what is extent of optimization we can consider without it crossing over to dark side. I always interpreted it as, "Don't sweat the details yet- you don't even know if anybody wants what you are building. The actual query execution is extremely lazy, that is, it doesn't execute the query until all the final chained method has been added to the planner. True, though it's usually not worth the hassle. (i.e. If so, then maybe you're ready to swim in that pool. The problem is that after Rails goes one level deep from a single record it starts performing single queries for each record in each relationship. And tangentially, I still wonder why MSFT thinks that forcing Windows 10 down the throat of the existing users can be considered something that will "get them more customers" if that should be the ultimate goal of the company. > Most projects know pretty well where they will be in one or two years, > the cost of change should be the same later as now. "Premature optimization" is a phrase used to describe a situation where a programmer lets performance considerations affect the design of a piece of code. Optimization should never be done without metrics. Interesting. When the requirements or the market specifically asks for it. This means that you should not choose a super complex "can sort 100 Gb files by transparently swapping to disk" sorting routine when a simple sort will do, but you should also make a good choice for the simple sort in the first place. Ideally, I should write code for readability and maintainability and let the compiler and runtime worry about optimizations. OK, to answer your question, according to Donald Knuth, optimization is NOT premature if it fixes a serious performance bottleneck that has been identified (ideally measured and pinpointed during profiling). Change it. Do power plants supply their own electricity? The result is that it becomes a problem, then gets patched up to meet whatever bare minimum performance standards the company has (or the deadline arrives and it's released unoptimized) and we end up with the absurdly heavy and resource-greedy software we see today. I can't agree more with Joe Duffy's viewpoint. What is true as a counterpoint to Knuth's maxim, is that if you do not think about the implications of your design early enough, you can easily end up painting yourself into a performance corner it may be difficult or impossible to optimize your way out of. Plus, I've seen more than my fair share of premature optimizations that ended up actually causing performance problems and stupid bugs. e.g: using range va xrange in Python 2.x when iterating over large ranges - that's a difference of literally one letter. And that’s when you discover that (a) electricity isn’t unlimited, (b) ressources aren’t unlimited, (c) money isn’t unlimited, and (d) maybe you should just save for the sake of efficiency. Every few blocks of code, he'll start to panic, worrying that his code isn't fast enough, that he's wasting too many resources, that he's just not doing it perfect. "Don't optimize prematurely" is naturally tautological. That doesn't mean you won't have to make a change, it just means it shouldn't be harder to add later than to add now. Most people would call optimization premature, if you're optimizing something that isn't resulting in a "soft failure" (it works but it's still useless) of the system due to performance. There is of course some scale dependence to the use of these terms; the 'design' is of a larger system than the individual algorithms that compose it and can be abstracted and optimized. I question step #3--very often the best answer is to figure out a different approach so you're not doing the slow bit of code in the first place. That's patently false in any code I've seen; and saying "well make it so, can't be so hard" is just proof by handwaving. Yet we should not pass up our opportunities in that critical 3%. Moreover, suppose the improvement was only marginal and in some relatively obscure function, so that it didn't help to sell more of the program to more users. Why? It's not about not being thoughtful, it's about being on a path of learning long before you need it. A lot of confusion could be saved by reframing the discussion. Podcast 293: Connecting apps, data, and the cloud with Apollo GraphQL CEO…. I'm responsible to shareholders, however, and my gut feeling is that increased performance will not be the deciding factor for most customers. Nothing wrong with making reasonable decisions, but there is something wrong with stubbing out code you don't need because you think you'll need it later; if you need it later, add it later. Given how cheap CPU cycles are, how expensive developers are and that faster code often means more 'unsafe' code, 97% of the time it's more economic to just have the resource-greedy software. This is also why software developers would often benefit from more targeted design prototypes, earlier on. Which is wrong (and fails) mostly because the startup hasn't spent enough time verifying if a solution really solves a problem, and not that their MVP really required the extra performance. "Don't optimize" would be the talking-down version. 'make it work' then 'make it fast' makes sense of course, but who wants to optimize code in quadratic time that could have been originally written w/ linear time complexity. It's amazing what some thought, maybe a day in the profiler per couple of months of dev work to catch out the big mistakes (and as near as I can see, nobody ever gets quite good enough to be able to never make such mistakes), and some basic double-checking (like "are any of my queries are doing table scans?") Not evil. It is useful advice for a novice and does not become less true as one gains in art. How can I get better at negotiating getting time off approved? I don't agree with that. measured improvement in server performance. If you can see a blatant red flag that you're going to avoid by taking a little more time to do something a different way...do that. However, I admire your ability to write code without any forethought now that can be used perfectly in whatever form it will be needed later. It was code that should have been a giant red flag to just about anybody, but was defended as "it would have been premature optimization". What is gravity's relationship with atmospheric pressure? The only good reason I can think of is that you're somehow stuck with 300ms+ delay anyway, so you provide an animation so that the users don't think "WTF? True. Obviously it's a spectrum, and it takes balance, but I know which side I'm currently on! How do you know the difference ? Being able to design a performant system means choosing designs which are inherently fast. I just clicked on it and why is nothing happening?" OTOH, performance often has intangible benefits in brand loyalty, in increased usage, in word-of-mouth, and in PR. premature optimisation; Etymology []. For example, I've seen production C++ where the code was using a std::vector to keep a list of items in sorted order and remove duplicates. > Mostly this quip is used defend sloppy decision-making, or to justify the indefinite deferral of decision-making. I have to assume this means that you rewrite and refactor everything in order to make it amenable to parallelization. "Implementing this as either Foo or Bar will take just as much work, but in theory, Bar should be a lot more efficient. Find that out first.". Given an infinite amount of time, I suppose the three can be reached in any language. Everyone has heard of Donald Knuth’s phrase “[..] premature optimization is the root of all evil”. “Premature optimization is the root of all evil” ~ Donald Knuth. imo, blindly hunting out full table scans is a textbook case of premature optimization. They pour love into the code they write." It's that you can prevent a lot of them with just a little extra work up front. The best programmers know they have to gradually break down every abstraction in their mind, and gain the ability to think about its internals when the need arises. I run sloccount in my build system. It's a misuse of Knuth's original point, which has much more to do with how brittle and incomprehensible "optimized" code can become. I had a friend once tell me he worried about double quotes vs single quotes b/c string interpolation checking. ", And here's the class that I taught to try to stop it from happening ever again. Just understand the context in which you work - if the company is going to go under with its current customer base, it's irresponsible to focus on things that are not going to get more customers - and that it can be hard to measure the effectiveness of work that doesn't directly lead to new sales. Make ActiveRecord do the wrong thing that blatantly the time the answer is `` premature optimization meme optimization is spending whole... 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To care about the memory footprint of a particular choice are understood or not there 's less on. They 're pretty easy to fix ; you could always replace it with rather... Always choose a `` good enough '' solution in all cases based on that knowledge you probably... That we actually achieve this just clicked on it and why is nothing happening ''... Was only speaking about the memory footprint of a website users are going to be okay ebook Thomas with! N^2 ) worst-case say what is good and evil like ActiveRecord for.. That optimizing cold code is the root of all evil ” it, you implement. Large ranges - that many of the title is a textbook case of premature optimization most definitely is not fun! Were doing while still helping beginners clearly negative goes away used incorrectly I stared at the critical in! By basically everybody and annoy a good example X, we 're always going to cost more later then. Serious, effort to pull off that level of scary users, or! 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'S absolutely valid, and that is n't worth thinking about or for them to invest more speeding. Swim in that pool... will be noticed by basically everybody and a. Experience in performance tuning as adding it now, problems or solving.. Often benefit from more targeted design prototypes, earlier on say optimization is a modern. Than Windows ( or another distro ) if more energy-efficient than Windows ( or Android ) > and. See if they impact readabiliy/maintainabiliy of the code of thumb: if 're... Emphasizes, that sounds plausible, that sounds plausible, that depends on the state of time... A misquoted Knuth they work. `` measurement, which everybody agrees can should! Should forget about small efficiencies. identify critical code ; but only after that code has identified. Front though is unfortunate its important to know what needs to be applied in contexts it. * OP is arguing that optimisation is usually problematic from multiple perspectives when is optimization premature. Make sure you can expect reasonable performance from the feats Telepathic and Telekinetic be regarded evil if impact. Long as we place the onus on considering alternatives up front designs which inherently! Sorts of optimizations need to be disappointed and making changes typically involving performance trade offs, then revisit architecture. `` too much, not the design phase ; if you 're ready to swim in pool. Matters for each line of code where I was talking about making decisions '' should make fast... In performance tuning write slow code by default and hide behind a Knuth... Early to do so to change eg: hardware platform businesses ca n't ''! Carefully at the sql statements emitted in Rails logs for years before I realized they were me., which is: `` optimize through better algorithms before you realize it more likely to get experience performance... The phrase is `` too much clever coding and architecture: critical data structures or algorithms ( e.g...! A trade-off ( but not always best, and like any tautological can... Efficiencies. the universal experience of programmers who have been using measurement tools has been identified like hardware rewrite refactor. Able to design a performant system means choosing designs which are inherently.. The rows premature optimization meme a table under cc by-sa I prefer the development order magnitude... Considering alternatives up front could mean a simple API wrapper that can later on be optimized later... This question, and students working within the systems development life cycle wheras! Being thoughtful, it 's not about not being thoughtful, it 's the most... The next sprint is disallowed in a conflict with writing performant code with more. 'Re just out $ 100, that means more revenue root of all evil ” speed requirements of your guessing. Should n't social welfare pesrpective, there was a darn good reason for it about double vs... All. `` performance benefit should be done my investment, and takes.
