2 Commits

Author	SHA1	Message	Date
Josh Bleecher Snyder	46a75870ad	runtime: speed up fastrand() % n ... This occurs a fair amount in the runtime for non-power-of-two n. Use an alternative, faster formulation. name old time/op new time/op delta Fastrandn/2-8 4.45ns ± 2% 2.09ns ± 3% -53.12% (p=0.000 n=14+14) Fastrandn/3-8 4.78ns ±11% 2.06ns ± 2% -56.94% (p=0.000 n=15+15) Fastrandn/4-8 4.76ns ± 9% 1.99ns ± 3% -58.28% (p=0.000 n=15+13) Fastrandn/5-8 4.96ns ±13% 2.03ns ± 6% -59.14% (p=0.000 n=15+15) name old time/op new time/op delta SelectUncontended-8 33.7ns ± 2% 33.9ns ± 2% +0.70% (p=0.000 n=49+50) SelectSyncContended-8 1.68µs ± 4% 1.65µs ± 4% -1.54% (p=0.000 n=50+45) SelectAsyncContended-8 282ns ± 1% 277ns ± 1% -1.50% (p=0.000 n=48+43) SelectNonblock-8 5.31ns ± 1% 5.32ns ± 1% ~ (p=0.275 n=45+44) SelectProdCons-8 585ns ± 3% 577ns ± 2% -1.35% (p=0.000 n=50+50) GoroutineSelect-8 1.59ms ± 2% 1.59ms ± 1% ~ (p=0.084 n=49+48) Updates #16213 Change-Id: Ib555a4d7da2042a25c3976f76a436b536487d5b7 Reviewed-on: https://go-review.googlesource.com/36932 Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org> Reviewed-by: Keith Randall <khr@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>	2017-02-14 00:01:22 +00:00
Sokolov Yura	d03c124860	runtime: implement fastrand in go ... So it could be inlined. Using bit-tricks it could be implemented without condition (improved trick version by Minux Ma). Simple benchmark shows it is faster on i386 and x86_64, though I don't know will it be faster on other architectures? benchmark old ns/op new ns/op delta BenchmarkFastrand-3 2.79 1.48 -46.95% BenchmarkFastrandHashiter-3 25.9 24.9 -3.86% Change-Id: Ie2eb6d0f598c0bb5fac7f6ad0f8b5e3eddaa361b Reviewed-on: https://go-review.googlesource.com/34782 Reviewed-by: Minux Ma <minux@golang.org> Run-TryBot: Minux Ma <minux@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>	2017-02-10 19:16:29 +00:00