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// Copyright 2013 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.
// Futex is only available on DragonFly BSD, FreeBSD and Linux.
// The race detector emits calls to split stack functions so it breaks
// the test.
// +build dragonfly freebsd linux
// +build !race
package runtime_test
import (
"runtime"
"sync"
"sync/atomic"
"testing"
"time"
)
type futexsleepTest struct {
mtx uint32
ns int64
msg string
ch chan *futexsleepTest
}
var futexsleepTests = []futexsleepTest{
beforeY2038: {mtx: 0, ns: 86400 * 1e9, msg: "before the year 2038"},
afterY2038: {mtx: 0, ns: (1<<31 + 100) * 1e9, msg: "after the year 2038"},
}
const (
beforeY2038 = iota
afterY2038
)
func TestFutexsleep(t *testing.T) {
if runtime.GOMAXPROCS(0) > 1 {
// futexsleep doesn't handle EINTR or other signals,
// so spurious wakeups may happen.
t.Skip("skipping; GOMAXPROCS>1")
}
start := time.Now()
var wg sync.WaitGroup
for i := range futexsleepTests {
tt := &futexsleepTests[i]
tt.mtx = 0
tt.ch = make(chan *futexsleepTest, 1)
wg.Add(1)
go func(tt *futexsleepTest) {
runtime.Entersyscall()
runtime.Futexsleep(&tt.mtx, 0, tt.ns)
runtime.Exitsyscall()
tt.ch <- tt
wg.Done()
}(tt)
}
loop:
for {
select {
case tt := <-futexsleepTests[beforeY2038].ch:
t.Errorf("futexsleep test %q finished early after %s", tt.msg, time.Since(start))
break loop
case tt := <-futexsleepTests[afterY2038].ch:
// Looks like FreeBSD 10 kernel has changed
// the semantics of timedwait on userspace
// mutex to make broken stuff look broken.
switch {
case runtime.GOOS == "freebsd" && runtime.GOARCH == "386":
t.Log("freebsd/386 may not work correctly after the year 2038, see golang.org/issue/7194")
default:
t.Errorf("futexsleep test %q finished early after %s", tt.msg, time.Since(start))
break loop
}
case <-time.After(time.Second):
break loop
}
}
for i := range futexsleepTests {
tt := &futexsleepTests[i]
atomic.StoreUint32(&tt.mtx, 1)
runtime.Futexwakeup(&tt.mtx, 1)
}
wg.Wait()
}
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