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