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| author | Dmitriy Vyukov <dvyukov@google.com> | 2014-08-16 09:07:55 +0400 |
|---|---|---|
| committer | Dmitriy Vyukov <dvyukov@google.com> | 2014-08-16 09:07:55 +0400 |
| commit | c6fe53a230e70bbb7a5582afe96cacf174eb0335 (patch) | |
| tree | 09dc7204610f11bedace8deab9f4df42b8c5b1b9 /src/pkg/runtime | |
| parent | 78cc89ce6740057bfbf9da211102c75659f83c89 (diff) | |
| download | go-c6fe53a230e70bbb7a5582afe96cacf174eb0335.tar.xz | |
runtime: mark with non-atomic operations when GOMAXPROCS=1
Perf builders show 3-5% GC pause increase with GOMAXPROCS=1 when marking with atomic ops:
http://goperfd.appspot.com/perfdetail?commit=a8a6e765d6a87f7ccb71fd85a60eb5a821151f85&commit0=3b864e02b987171e05e2e9d0840b85b5b6476386&kind=builder&builder=linux-amd64&benchmark=http
LGTM=rlh
R=golang-codereviews, rlh
CC=dave, golang-codereviews, khr, rsc
https://golang.org/cl/128340043
Diffstat (limited to 'src/pkg/runtime')
| -rw-r--r-- | src/pkg/runtime/mgc0.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/src/pkg/runtime/mgc0.c b/src/pkg/runtime/mgc0.c index 59dfd51e65..f46d329017 100644 --- a/src/pkg/runtime/mgc0.c +++ b/src/pkg/runtime/mgc0.c @@ -451,7 +451,8 @@ scanblock(byte *b, uintptr n, byte *ptrmask) // quadruple is already marked. Otherwise we resort to CAS // loop for marking. bits8 = xbits>>(shift&~7); - if((bits8&(bitMask|(bitMask<<gcBits))) != (bitBoundary|(bitBoundary<<gcBits))) + if((bits8&(bitMask|(bitMask<<gcBits))) != (bitBoundary|(bitBoundary<<gcBits)) || + work.nproc == 1) ((uint8*)bitp)[shift/8] = bits8 | (bitMarked<<(shift&7)); else { for(;;) { |