Use smaller discriminants for generators by jonas-schievink · Pull Request #69837 · rust-lang/rust (original) (raw)

Running this on async-std's mutex.rs bench shows some unfortunate regressions that I compared the wrong compilers, there are no significant perf regressions on this benchmark (it got a bit faster, even):

master:

test contention    ... bench:   1,028,149 ns/iter (+/- 42,225)
test create        ... bench:           3 ns/iter (+/- 0)
test no_contention ... bench:     954,627 ns/iter (+/- 30,982)

This PR

test contention    ... bench:   1,025,108 ns/iter (+/- 87,055)
test create        ... bench:           3 ns/iter (+/- 0)
test no_contention ... bench:     886,630 ns/iter (+/- 24,225)