Re:Rust programs versus Go
by jerf on Wednesday May 16, 2018 @02:14PM
(#17084937)
"I'd also like to push back on the idea that perf comparisons are meaningless if one implementation has degenerate cases."
That's not what I said. I said, you can't use "X times faster" comparisons if the O() of the two algorithms in question are not more-or-less the same. That does not prevent you from still characterizing performance differences. You just can't do it via "X times faster" statements, because those are only well-defined for things separated by linear factors, and practically defined for things separated by practically linear factors. f(x) = x^2 is not "2 times bigger" than g(x) = x, or any number of "times bigger", whereas h(x) = 3x + 5 can be reasonably said to be "3 times bigger" than i(x) = x + 50, even though it is not the case that h(x) = 3i(x).
That's not what I said. I said, you can't use "X times faster" comparisons if the O() of the two algorithms in question are not more-or-less the same. That does not prevent you from still characterizing performance differences. You just can't do it via "X times faster" statements, because those are only well-defined for things separated by linear factors, and practically defined for things separated by practically linear factors. f(x) = x^2 is not "2 times bigger" than g(x) = x, or any number of "times bigger", whereas h(x) = 3x + 5 can be reasonably said to be "3 times bigger" than i(x) = x + 50, even though it is not the case that h(x) = 3i(x).