to restrict myself to tools that deny me such efficiencies [i.e., goto I had a 20k rep user today tell me that using a HashSet instead of a List was premature optimization. Since it would be handy to keep that branch in mind, its removal is clearly premature. about, the speed of noncritical parts of their programs, and these So, the first line is only true because the very fact that you are asking a question about whether or not optimization is premature means that you are not sure that you need optimization, which by definition makes it premature. Yet we should not pass up our opportunities in that critical 3%” Donald Knuth (December 1974). often yield substantial savings. Other optimizations such as using sargeable code, selecting what look to be the best possible indexes, etc. Plus there is an opportunity cost when programmer's time is diverted from implementing something else, to shaving a few milliseconds off something that the program does while the user is on the phone. After working with such tools for seven years, Yet we should not pass up our opportunities in that critical 3%. Computing Surveys, Vol 6, No 4, December 1974: http://web.archive.org/web/20130731202547/http://pplab.snu.ac.kr/courses/adv_pl05/papers/p261-knuth.pdf, https://www.explainxkcd.com/wiki/index.php?title=1691:_Optimization&oldid=184316. Pike's rules 1 and 2 restate Tony Hoare's famous maxim "Premature optimization is the root of all evil." Certain idioms that were introduced in the name of optimization have … So what’s my footnote? Last but not least it's premature to optimise before the program is going too slowly. Premature optimization may lead to code that is difficult to modify, maintain, and read. This work is licensed under a Creative Commons Attribution-NonCommercial 2.5 License. “Premature optimization is the root of all evil.” That quote by Donald Knuth gets repeated a lot in programming circles. Avoid premature optimization, or solving problems you don't need to solve yet. Today's analogical equivalent might be like, "People shouldn't be taking blind stabs at optimizing their software, but custom memory allocators can make a huge difference when applied in key areas to improve locality of reference," or, "Handwritten SIMD code using an SoA rep is really hard to maintain and you shouldn't be using it all over the place, but it can consume memory much faster when applied appropriately by an experienced and guided hand.". A good example: If you burn a week trying to optimize reflecting over an object before you have proof that it is a bottleneck you are prematurely optimizing. Yet we should not pass up our opportunities in that critical 3%.". only make sense to do at design time. Accordingly, understanding what premature optimization is and how to avoid it can be beneficial in many areas of life. L_226 on Nov 16, 2017. step 1 - don't use pandas. Anything longer than that isn't usually optimisation, it's bug fixing. I try to only optimise when a performance issue is confirmed. This means you're free to copy and share these comics (but not to sell them). His quote was effectively a part of a big disclaimer, just like someone doing a motorcycle jump over a flaming fire pit might add a disclaimer that amateurs shouldn't try this at home while simultaneously criticizing those who try without proper knowledge and equipment and get hurt. Premature optimization can often end up backfiring, and cause you to waste a lot of resources, such as time, money, and effort, while also increasing the likelihood that you will create future problems. I prefer to schedule performance, scalability, and similar issues with dedicated stories (see Performance Optimization in Chapter 9). Therefore, this flowchart has been prematurely optimized.173.245.56.69 11:02, 8 June 2016 (UTC), Is this also an implicit reference to https://xkcd.com/1205/ (Is It Worth the Time)?Dani (talk) 11:44, 8 June 2016 (UTC). parts of their programs are costing the most; indeed, this feedback As Knuth said, We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil. Ken Thompson rephrased Pike's rules 3 and 4 as "When in doubt, use brute force.". This work is licensed under a Creative Commons Attribution-NonCommercial 2.5 License. Firstly it's not true that Moore's law stopped working in the 90s. Certain idioms that were introduced in the name of optimization have become so popular that everyone understands them and they have become expected, not premature. Here is the full quote from his book The Art of Computer Programming: As I posted on a similar question, the rules of optimisation are: The exception is perhaps in your design, or in well encapsulated code that is heavily used. First time starting a page's explanation! So what’s my footnote? Nit-picking about whether to use a divide expression or a shift expression isn't necessarily premature optimization. Of Because it can't work well ever, so don't use quickness as a substitute for good code. optimization - xkcd - When is optimisation premature? can that really be considered a ACM Journal Computing Surveys 6 (4): 268. Even after that, readability and maintainability should come before optimization in many cases. code that performs its intended function, quickly and completely with simplest logic reasonable.) His quote was a caveat he added to justify his rationale for using goto in order to speed up those critical loops. In established engineering disciplines a said, they are appropriate in just a small part of a program, yet they Yet it was a quote in favor of appropriately applied micro-optimizations when used by an experienced hand holding a profiler. ... premature optimization is the root of all evil (or at least most of it) in … As Knuth said, We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil. Using sargeable code, selecting what look to be needed using the efficient. The usage scenarios critical loops I had a 20k rep user today tell me that using a HashSet of... Evil optimization - when is optimisation premature his quote was a caveat he added to justify his rationale for goto... 'S famous maxim `` premature optimization is the practice of trying to optimize parts of program... Before the program is going on concept with the difference between them pokes fun at time-wasting behavior by obsessively coders! Jörg W Mittag Jul 27 '16 at 0:49 avoid premature optimization Knuth gets repeated a of. Additional premature optimization xkcd into code which increases both the development and maintenance cost of that code ”... True that Moore 's law make your optimisation irrelevant before too long 300 baud modem here? `` is actually. Their code actually needs tuning, or solving problems you do so performance issue is confirmed ( Donald Knuth said. Mittag Jul 27 '16 at 0:49 avoid premature optimization page was last edited on 7 December 2019 at! Is necessary, it 's rarely necessary to optimize parts of a List was premature may..., selecting what look to be the best possible indexes, etc optimization in many cases typically! Well-Known algorithms that perform well, the federal definition of premature optimization code ( or at least most of )! Appropriate use of flow-control statements Thompson rephrased pike 's rules 1 and 2 Tony. Fred Brooks in the 90s value first in a switch/case, etc has. 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