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// Copyright 2009 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_test
import (
"runtime"
. "sync"
"sync/atomic"
"testing"
)
func BenchmarkSemaUncontended(b *testing.B) {
type PaddedSem struct {
sem uint32
pad [32]uint32
}
const CallsPerSched = 1000
procs := runtime.GOMAXPROCS(-1)
N := int32(b.N / CallsPerSched)
c := make(chan bool, procs)
for p := 0; p < procs; p++ {
go func() {
sem := new(PaddedSem)
for atomic.AddInt32(&N, -1) >= 0 {
runtime.Gosched()
for g := 0; g < CallsPerSched; g++ {
Runtime_Semrelease(&sem.sem)
Runtime_Semacquire(&sem.sem)
}
}
c <- true
}()
}
for p := 0; p < procs; p++ {
<-c
}
}
func benchmarkSema(b *testing.B, block, work bool) {
const CallsPerSched = 1000
const LocalWork = 100
procs := runtime.GOMAXPROCS(-1)
N := int32(b.N / CallsPerSched)
c := make(chan bool, procs)
c2 := make(chan bool, procs/2)
sem := uint32(0)
if block {
for p := 0; p < procs/2; p++ {
go func() {
Runtime_Semacquire(&sem)
c2 <- true
}()
}
}
for p := 0; p < procs; p++ {
go func() {
foo := 0
for atomic.AddInt32(&N, -1) >= 0 {
runtime.Gosched()
for g := 0; g < CallsPerSched; g++ {
Runtime_Semrelease(&sem)
if work {
for i := 0; i < LocalWork; i++ {
foo *= 2
foo /= 2
}
}
Runtime_Semacquire(&sem)
}
}
c <- foo == 42
Runtime_Semrelease(&sem)
}()
}
if block {
for p := 0; p < procs/2; p++ {
<-c2
}
}
for p := 0; p < procs; p++ {
<-c
}
}
func BenchmarkSemaSyntNonblock(b *testing.B) {
benchmarkSema(b, false, false)
}
func BenchmarkSemaSyntBlock(b *testing.B) {
benchmarkSema(b, true, false)
}
func BenchmarkSemaWorkNonblock(b *testing.B) {
benchmarkSema(b, false, true)
}
func BenchmarkSemaWorkBlock(b *testing.B) {
benchmarkSema(b, true, true)
}
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