// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package sync_test
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import (
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"runtime"
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. "sync"
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"testing"
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)
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func BenchmarkSemaUncontended(b *testing.B) {
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type PaddedSem struct {
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sem uint32
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pad [32]uint32
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}
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b.RunParallel(func(pb *testing.PB) {
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sem := new(PaddedSem)
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for pb.Next() {
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Runtime_Semrelease(&sem.sem, false)
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Runtime_Semacquire(&sem.sem)
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}
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})
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}
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func benchmarkSema(b *testing.B, block, work bool) {
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if b.N == 0 {
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return
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}
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sem := uint32(0)
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if block {
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done := make(chan bool)
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go func() {
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for p := 0; p < runtime.GOMAXPROCS(0)/2; p++ {
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Runtime_Semacquire(&sem)
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}
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done <- true
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}()
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defer func() {
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<-done
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}()
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}
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b.RunParallel(func(pb *testing.PB) {
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foo := 0
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for pb.Next() {
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Runtime_Semrelease(&sem, false)
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if work {
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for i := 0; i < 100; i++ {
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foo *= 2
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foo /= 2
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}
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}
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Runtime_Semacquire(&sem)
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}
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_ = foo
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Runtime_Semrelease(&sem, false)
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})
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}
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func BenchmarkSemaSyntNonblock(b *testing.B) {
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benchmarkSema(b, false, false)
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}
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func BenchmarkSemaSyntBlock(b *testing.B) {
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benchmarkSema(b, true, false)
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}
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func BenchmarkSemaWorkNonblock(b *testing.B) {
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benchmarkSema(b, false, true)
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}
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func BenchmarkSemaWorkBlock(b *testing.B) {
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benchmarkSema(b, true, true)
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}
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