> Usually people say “premature optimization is the root of all evil” to say “small optimizations are not worth it” but […] Instead what matters is whether you

> Usually people say “premature optimization is the root of all evil” to say “small optimizations are not worth it” but […] Instead what matters is whether you benchmarked your code and whether you determined that this optimization actually makes a difference to the runtime of the program. In my experience the latter is actually often expressed. What else would “premature” mean, other than you don’t know yet whether the optimization is worth it? The disagreement is usually more about small inefficiencies that may compound in the large but whose combined effects are difficult to assess, compiler/platform/environment-dependent optimizations that may be pessimizations elsewhere, reasoning about asymptotic runtime (which shouldn’t require benchmarking — but with cache locality effects sometimes it does), the validity of microbenchmarks, and so on.