It's also Knuth quoting Tony Hoare, a man who I highly recommend everyone familiarize themselves with, he's a wonderful speaker and is extremely intelligent. T

It's also Knuth quoting Tony Hoare, a man who I highly recommend everyone familiarize themselves with, he's a wonderful speaker and is extremely intelligent. The context of the quote from both Hoare and Knuth is critical, and is always left out. "We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil." ie: 3% of the time you should absolutely care about 'small' efficiencies. Given that most programs spend almost all of their time in a few places, this is hardly surprising, and 3% is actually a fairly sizable amount of code to optimize to the degree which the paper is discussing (most people are rarely dropping to tools like goto for performance). And, from the same paper (Structured Programming with goto Statements): "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 pennywise-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 believe 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." In other words, we should not write slower code when we can help it. Small efficiencies are well worth attaining in the general case, and the fears of writing 'unreadable' code because it's fast are mostly unfounded. I believe this has never been truer. It's easier than ever to create highly tuned code that's hidden behind a 0 cost abstraction, and it's well worth it to tune that code for simple and obvious wins - we should never strive for inefficiency, as so many seem to advocate.