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.

// GOMAXPROCS=10 gotest

package sync_test

import (
        "runtime"
        . "sync"
        "sync/atomic"
        "testing"
)

func HammerSemaphore(s *uint32, loops int, cdone chan bool) {
        for i := 0; i < loops; i++ {
                runtime.Semacquire(s)
                runtime.Semrelease(s)
        }
        cdone <- true
}

func TestSemaphore(t *testing.T) {
        s := new(uint32)
        *s = 1
        c := make(chan bool)
        for i := 0; i < 10; i++ {
                go HammerSemaphore(s, 1000, c)
        }
        for i := 0; i < 10; i++ {
                <-c
        }
}

func BenchmarkUncontendedSemaphore(b *testing.B) {
        s := new(uint32)
        *s = 1
        HammerSemaphore(s, b.N, make(chan bool, 2))
}

func BenchmarkContendedSemaphore(b *testing.B) {
        b.StopTimer()
        s := new(uint32)
        *s = 1
        c := make(chan bool)
        defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(2))
        b.StartTimer()

        go HammerSemaphore(s, b.N/2, c)
        go HammerSemaphore(s, b.N/2, c)
        <-c
        <-c
}

func HammerMutex(m *Mutex, loops int, cdone chan bool) {
        for i := 0; i < loops; i++ {
                m.Lock()
                m.Unlock()
        }
        cdone <- true
}

func TestMutex(t *testing.T) {
        m := new(Mutex)
        c := make(chan bool)
        for i := 0; i < 10; i++ {
                go HammerMutex(m, 1000, c)
        }
        for i := 0; i < 10; i++ {
                <-c
        }
}

func TestMutexPanic(t *testing.T) {
        defer func() {
                if recover() == nil {
                        t.Fatalf("unlock of unlocked mutex did not panic")
                }
        }()

        var mu Mutex
        mu.Lock()
        mu.Unlock()
        mu.Unlock()
}

func BenchmarkMutexUncontended(b *testing.B) {
        type PaddedMutex struct {
                Mutex
                pad [128]uint8
        }
        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() {
                        var mu PaddedMutex
                        for atomic.AddInt32(&N, -1) >= 0 {
                                runtime.Gosched()
                                for g := 0; g < CallsPerSched; g++ {
                                        mu.Lock()
                                        mu.Unlock()
                                }
                        }
                        c <- true
                }()
        }
        for p := 0; p < procs; p++ {
                <-c
        }
}

func benchmarkMutex(b *testing.B, slack, work bool) {
        const (
                CallsPerSched  = 1000
                LocalWork      = 100
                GoroutineSlack = 10
        )
        procs := runtime.GOMAXPROCS(-1)
        if slack {
                procs *= GoroutineSlack
        }
        N := int32(b.N / CallsPerSched)
        c := make(chan bool, procs)
        var mu Mutex
        for p := 0; p < procs; p++ {
                go func() {
                        foo := 0
                        for atomic.AddInt32(&N, -1) >= 0 {
                                runtime.Gosched()
                                for g := 0; g < CallsPerSched; g++ {
                                        mu.Lock()
                                        mu.Unlock()
                                        if work {
                                                for i := 0; i < LocalWork; i++ {
                                                        foo *= 2
                                                        foo /= 2
                                                }
                                        }
                                }
                        }
                        c <- foo == 42
                }()
        }
        for p := 0; p < procs; p++ {
                <-c
        }
}

func BenchmarkMutex(b *testing.B) {
        benchmarkMutex(b, false, false)
}

func BenchmarkMutexSlack(b *testing.B) {
        benchmarkMutex(b, true, false)
}

func BenchmarkMutexWork(b *testing.B) {
        benchmarkMutex(b, false, true)
}

func BenchmarkMutexWorkSlack(b *testing.B) {
        benchmarkMutex(b, true, true)
}