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mirror of https://github.com/golang/go synced 2024-11-08 04:36:11 -07:00
go/src/pkg/sync/runtime.go
Dmitriy Vyukov 5a20b4a6a9 sync: faster Cond
The new version does not require any memory allocations and is 30-50% faster.
Also detect and painc if Cond is copied after first.

benchmark            old ns/op    new ns/op    delta
BenchmarkCond1             317          195  -38.49%
BenchmarkCond1-2           875          607  -30.63%
BenchmarkCond1-4          1116          548  -50.90%
BenchmarkCond1-8          1013          613  -39.49%
BenchmarkCond1-16          983          450  -54.22%
BenchmarkCond2             559          352  -37.03%
BenchmarkCond2-2          1916         1378  -28.08%
BenchmarkCond2-4          1518         1322  -12.91%
BenchmarkCond2-8          2313         1291  -44.19%
BenchmarkCond2-16         1885         1078  -42.81%
BenchmarkCond4            1070          614  -42.62%
BenchmarkCond4-2          4899         3047  -37.80%
BenchmarkCond4-4          3813         3006  -21.16%
BenchmarkCond4-8          3605         3045  -15.53%
BenchmarkCond4-16         4148         2637  -36.43%
BenchmarkCond8            2086         1264  -39.41%
BenchmarkCond8-2          9961         6736  -32.38%
BenchmarkCond8-4          8135         7689   -5.48%
BenchmarkCond8-8          9623         7517  -21.89%
BenchmarkCond8-16        11661         8093  -30.60%

R=sougou, rsc, bradfitz, r
CC=golang-dev
https://golang.org/cl/11573043
2013-08-13 14:45:36 +04:00

37 lines
1.2 KiB
Go

// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package sync
import "unsafe"
// defined in package runtime
// Semacquire waits until *s > 0 and then atomically decrements it.
// It is intended as a simple sleep primitive for use by the synchronization
// library and should not be used directly.
func runtime_Semacquire(s *uint32)
// Semrelease atomically increments *s and notifies a waiting goroutine
// if one is blocked in Semacquire.
// It is intended as a simple wakeup primitive for use by the synchronization
// library and should not be used directly.
func runtime_Semrelease(s *uint32)
// Opaque representation of SyncSema in runtime/sema.goc.
type syncSema [3]uintptr
// Syncsemacquire waits for a pairing Syncsemrelease on the same semaphore s.
func runtime_Syncsemacquire(s *syncSema)
// Syncsemrelease waits for n pairing Syncsemacquire on the same semaphore s.
func runtime_Syncsemrelease(s *syncSema, n uint32)
// Ensure that sync and runtime agree on size of syncSema.
func runtime_Syncsemcheck(size uintptr)
func init() {
var s syncSema
runtime_Syncsemcheck(unsafe.Sizeof(s))
}