Subversion Repositories openrisc

// 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"
)

type one int

func (o *one) Increment() {
        *o++
}

func run(once *Once, o *one, c chan bool) {
        once.Do(func() { o.Increment() })
        c <- true
}

func TestOnce(t *testing.T) {
        o := new(one)
        once := new(Once)
        c := make(chan bool)
        const N = 10
        for i := 0; i < N; i++ {
                go run(once, o, c)
        }
        for i := 0; i < N; i++ {
                <-c
        }
        if *o != 1 {
                t.Errorf("once failed: %d is not 1", *o)
        }
}

func BenchmarkOnce(b *testing.B) {
        const CallsPerSched = 1000
        procs := runtime.GOMAXPROCS(-1)
        N := int32(b.N / CallsPerSched)
        var once Once
        f := func() {}
        c := make(chan bool, procs)
        for p := 0; p < procs; p++ {
                go func() {
                        for atomic.AddInt32(&N, -1) >= 0 {
                                runtime.Gosched()
                                for g := 0; g < CallsPerSched; g++ {
                                        once.Do(f)
                                }
                        }
                        c <- true
                }()
        }
        for p := 0; p < procs; p++ {
                <-c
        }
}