3 ms·

premature optimization is the root of all evil.

• mpweiher 10y ago
  The actual quote is a bit different: "We should forget about small efficiencies, say about 97% of the time; premature optimization is the root of all evil." It goes on: "Yet we should not pass up our opportunities in that critical 3%. A good programmer will not be lulled into complacency by such reasoning, he will be wise to look carefully at the critical code; but only after that code has been identified." Just before that section: "The conventional wisdom shared by many of today's software engineers calls for ignoring efficiency in the small; but I believe this is simply an overreaction to the abuses they see being practiced by penny- wise-and-pound-foolish programmers, who can't debug or maintain their "optimized" programs. In established engineering disciplines a 12 % improvement, easily obtained, is never considered marginal; and I believ the same viewpoint should prevail in software engineering. Of course I wouldn't bother making such optimizations on a one-shot job, but when it's a question of preparing quality programs, I don't want to restrict myself to tools that deny me such efficiencies" From "Structured Programming with go to statements" Knuth, 1974.
  • tehlike 10y ago
    I think my emphasis was still fair, even though it is probably a misquote. There are usually many bottlenecks in any given system, be it lack of proper parallelization, waiting on xyz while you could use that opportunity to do other tasks and so on that language tend to account for small part of these. Sure, if you are hitting the limit of that kind of optimizations, language could be the next thing you want to use to optimize further, but usually systems are far from that.