diff options
| author | Dave Cheney <dave@cheney.net> | 2013-08-06 07:51:37 +1000 |
|---|---|---|
| committer | Dave Cheney <dave@cheney.net> | 2013-08-06 07:51:37 +1000 |
| commit | 8ce8adbe7a194cba2819b533b603d92df40fe799 (patch) | |
| tree | c7d3ff9364633dee92064125e46ec43f85929309 /src/pkg/runtime/slice.c | |
| parent | 19e292268896c245c781e711ae3fff5ff5e127e5 (diff) | |
| download | go-8ce8adbe7a194cba2819b533b603d92df40fe799.tar.xz | |
runtime: tune append crossover on amd64 and 386
Fixes #4963.
Sets the append crossover to 0 on intel platforms.
Results for linux/amd64 Core i5 SNB
benchmark old ns/op new ns/op delta
BenchmarkAppend 102 104 +1.96%
BenchmarkAppend1Byte 10 11 +0.92%
BenchmarkAppend4Bytes 15 11 -28.10%
BenchmarkAppend7Bytes 17 12 -32.58%
BenchmarkAppend8Bytes 18 12 -36.17%
BenchmarkAppend15Bytes 24 11 -55.02%
BenchmarkAppend16Bytes 25 11 -56.03%
BenchmarkAppend32Bytes 11 12 +4.31%
BenchmarkAppendStr1Byte 8 9 +13.99%
BenchmarkAppendStr4Bytes 11 9 -17.52%
BenchmarkAppendStr8Bytes 14 9 -35.70%
BenchmarkAppendStr16Bytes 21 9 -55.19%
BenchmarkAppendStr32Bytes 10 10 -5.66%
BenchmarkAppendSpecialCase 49 52 +7.96%
Results for linux/386 Atom(TM) CPU 330 @ 1.60GHz
benchmark old ns/op new ns/op delta
BenchmarkAppend 219 218 -0.46%
BenchmarkAppend1Byte 75 72 -3.44%
BenchmarkAppend4Bytes 92 73 -19.87%
BenchmarkAppend7Bytes 108 74 -31.20%
BenchmarkAppend8Bytes 116 74 -35.95%
BenchmarkAppend15Bytes 162 77 -52.22%
BenchmarkAppend16Bytes 169 77 -54.20%
BenchmarkAppend32Bytes 88 86 -2.38%
BenchmarkAppendStr1Byte 57 59 +3.32%
BenchmarkAppendStr4Bytes 72 59 -17.40%
BenchmarkAppendStr8Bytes 92 60 -34.70%
BenchmarkAppendStr16Bytes 141 63 -54.89%
BenchmarkAppendStr32Bytes 75 73 -2.64%
BenchmarkAppendSpecialCase 270 270 +0.00%
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/12440044
Diffstat (limited to 'src/pkg/runtime/slice.c')
| -rw-r--r-- | src/pkg/runtime/slice.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/src/pkg/runtime/slice.c b/src/pkg/runtime/slice.c index 3adbe51837..58086b61c7 100644 --- a/src/pkg/runtime/slice.c +++ b/src/pkg/runtime/slice.c @@ -95,7 +95,7 @@ runtime·appendslice(SliceType *t, Slice x, Slice y, Slice ret) p = ret.array+ret.len*w; q = y.array; w *= y.len; - if(w <= appendCrossover) { + if(appendCrossover > 0 && w <= appendCrossover) { if(p <= q || w <= p-q) // No overlap. while(w-- > 0) *p++ = *q++; @@ -148,7 +148,7 @@ runtime·appendstr(SliceType *t, Slice x, String y, Slice ret) w = y.len; p = ret.array+ret.len; q = y.str; - if(w <= appendCrossover) { + if(appendCrossover > 0 && w <= appendCrossover) { while(w-- > 0) *p++ = *q++; } else { |