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| author | Matthew Dempsky <mdempsky@google.com> | 2020-07-27 14:05:05 -0700 |
|---|---|---|
| committer | Matthew Dempsky <mdempsky@google.com> | 2020-08-18 20:05:41 +0000 |
| commit | 78a1064d5dd05fc669342df3a6a5e11d49749d85 (patch) | |
| tree | fa7423e63fc07b408b4c8ae68e14f541d78a2a56 /src/runtime/select.go | |
| parent | 30a68bfb806b5217932e280f5a5f521237e69077 (diff) | |
| download | go-78a1064d5dd05fc669342df3a6a5e11d49749d85.tar.gz go-78a1064d5dd05fc669342df3a6a5e11d49749d85.zip | |
runtime: remove scase.releasetime field
selectgo will report at most one block event, so there's no need to
keep a releasetime for every select case. It suffices to simply track
the releasetime of the case responsible for the wakeup.
Updates #40410.
Change-Id: I72679cd43dde80d7e6dbab21a78952a4372d1e79
Reviewed-on: https://go-review.googlesource.com/c/go/+/245122
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Diffstat (limited to 'src/runtime/select.go')
| -rw-r--r-- | src/runtime/select.go | 23 |
1 files changed, 10 insertions, 13 deletions
diff --git a/src/runtime/select.go b/src/runtime/select.go index 081db7bad4..2f8b139155 100644 --- a/src/runtime/select.go +++ b/src/runtime/select.go @@ -26,11 +26,10 @@ const ( // Known to compiler. // Changes here must also be made in src/cmd/internal/gc/select.go's scasetype. type scase struct { - c *hchan // chan - elem unsafe.Pointer // data element - kind uint16 - pc uintptr // race pc (for race detector / msan) - releasetime int64 + c *hchan // chan + elem unsafe.Pointer // data element + kind uint16 + pc uintptr // race pc (for race detector / msan) } var ( @@ -142,9 +141,6 @@ func selectgo(cas0 *scase, order0 *uint16, ncases int) (int, bool) { var t0 int64 if blockprofilerate > 0 { t0 = cputicks() - for i := 0; i < ncases; i++ { - scases[i].releasetime = -1 - } } // The compiler rewrites selects that statically have @@ -227,6 +223,7 @@ func selectgo(cas0 *scase, order0 *uint16, ncases int) (int, bool) { var casi int var cas *scase var caseSuccess bool + var caseReleaseTime int64 = -1 var recvOK bool for i := 0; i < ncases; i++ { casi = int(pollorder[i]) @@ -346,14 +343,14 @@ func selectgo(cas0 *scase, order0 *uint16, ncases int) (int, bool) { if k.kind == caseNil { continue } - if sglist.releasetime > 0 { - k.releasetime = sglist.releasetime - } if sg == sglist { // sg has already been dequeued by the G that woke us up. casi = int(casei) cas = k caseSuccess = sglist.success + if sglist.releasetime > 0 { + caseReleaseTime = sglist.releasetime + } } else { c = k.c if k.kind == caseSend { @@ -483,8 +480,8 @@ send: goto retc retc: - if cas.releasetime > 0 { - blockevent(cas.releasetime-t0, 1) + if caseReleaseTime > 0 { + blockevent(caseReleaseTime-t0, 1) } return casi, recvOK |