github.com/shijuvar/go@v0.0.0-20141209052335-e8f13700b70c/src/runtime/futex_test.go (about)

     1  // Copyright 2013 The Go Authors.  All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Futex is only available on DragonFly BSD, FreeBSD and Linux.
     6  // The race detector emits calls to split stack functions so it breaks
     7  // the test.
     8  
     9  // +build dragonfly freebsd linux
    10  // +build !race
    11  
    12  package runtime_test
    13  
    14  import (
    15  	"runtime"
    16  	"testing"
    17  	"time"
    18  )
    19  
    20  type futexsleepTest struct {
    21  	mtx uint32
    22  	ns  int64
    23  	msg string
    24  	ch  chan futexsleepTest
    25  }
    26  
    27  var futexsleepTests = []futexsleepTest{
    28  	beforeY2038: {mtx: 0, ns: 86400 * 1e9, msg: "before the year 2038", ch: make(chan futexsleepTest, 1)},
    29  	afterY2038:  {mtx: 0, ns: (1<<31 + 100) * 1e9, msg: "after the year 2038", ch: make(chan futexsleepTest, 1)},
    30  }
    31  
    32  const (
    33  	beforeY2038 = iota
    34  	afterY2038
    35  )
    36  
    37  func TestFutexsleep(t *testing.T) {
    38  	if runtime.GOMAXPROCS(0) > 1 {
    39  		// futexsleep doesn't handle EINTR or other signals,
    40  		// so spurious wakeups may happen.
    41  		t.Skip("skipping; GOMAXPROCS>1")
    42  	}
    43  
    44  	start := time.Now()
    45  	for _, tt := range futexsleepTests {
    46  		go func(tt futexsleepTest) {
    47  			runtime.Entersyscall(0)
    48  			runtime.Futexsleep(&tt.mtx, tt.mtx, tt.ns)
    49  			runtime.Exitsyscall(0)
    50  			tt.ch <- tt
    51  		}(tt)
    52  	}
    53  loop:
    54  	for {
    55  		select {
    56  		case tt := <-futexsleepTests[beforeY2038].ch:
    57  			t.Errorf("futexsleep test %q finished early after %s", tt.msg, time.Since(start))
    58  			break loop
    59  		case tt := <-futexsleepTests[afterY2038].ch:
    60  			// Looks like FreeBSD 10 kernel has changed
    61  			// the semantics of timedwait on userspace
    62  			// mutex to make broken stuff look broken.
    63  			switch {
    64  			case runtime.GOOS == "freebsd" && runtime.GOARCH == "386":
    65  				t.Log("freebsd/386 may not work correctly after the year 2038, see golang.org/issue/7194")
    66  			default:
    67  				t.Errorf("futexsleep test %q finished early after %s", tt.msg, time.Since(start))
    68  				break loop
    69  			}
    70  		case <-time.After(time.Second):
    71  			break loop
    72  		}
    73  	}
    74  	for _, tt := range futexsleepTests {
    75  		runtime.Futexwakeup(&tt.mtx, 1)
    76  	}
    77  }