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// Copyright 2017 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.
// +build darwin dragonfly freebsd linux netbsd openbsd solaris
package main
import (
"bytes"
"cmd/internal/traceviewer"
traceparser "internal/trace"
"io"
"runtime"
"runtime/trace"
"sync"
"syscall"
"testing"
"time"
)
// TestGoroutineInSyscall tests threads for timer goroutines
// that preexisted when the tracing started were not counted
// as threads in syscall. See golang.org/issues/22574.
func TestGoroutineInSyscall(t *testing.T) {
// Start one goroutine blocked in syscall.
//
// TODO: syscall.Pipe used to cause the goroutine to
// remain blocked in syscall is not portable. Replace
// it with a more portable way so this test can run
// on non-unix architecture e.g. Windows.
var p [2]int
if err := syscall.Pipe(p[:]); err != nil {
t.Fatalf("failed to create pipe: %v", err)
}
var wg sync.WaitGroup
defer func() {
syscall.Write(p[1], []byte("a"))
wg.Wait()
syscall.Close(p[0])
syscall.Close(p[1])
}()
wg.Add(1)
go func() {
var tmp [1]byte
syscall.Read(p[0], tmp[:])
wg.Done()
}()
// Start multiple timer goroutines.
allTimers := make([]*time.Timer, 2*runtime.GOMAXPROCS(0))
defer func() {
for _, timer := range allTimers {
timer.Stop()
}
}()
var timerSetup sync.WaitGroup
for i := range allTimers {
timerSetup.Add(1)
go func(i int) {
defer timerSetup.Done()
allTimers[i] = time.AfterFunc(time.Hour, nil)
}(i)
}
timerSetup.Wait()
// Collect and parse trace.
buf := new(bytes.Buffer)
if err := trace.Start(buf); err != nil {
t.Fatalf("failed to start tracing: %v", err)
}
trace.Stop()
res, err := traceparser.Parse(buf, "")
if err == traceparser.ErrTimeOrder {
t.Skipf("skipping due to golang.org/issue/16755 (timestamps are unreliable): %v", err)
} else if err != nil {
t.Fatalf("failed to parse trace: %v", err)
}
// Check only one thread for the pipe read goroutine is
// considered in-syscall.
c := viewerDataTraceConsumer(io.Discard, 0, 1<<63-1)
c.consumeViewerEvent = func(ev *traceviewer.Event, _ bool) {
if ev.Name == "Threads" {
arg := ev.Arg.(*threadCountersArg)
if arg.InSyscall > 1 {
t.Errorf("%d threads in syscall at time %v; want less than 1 thread in syscall", arg.InSyscall, ev.Time)
}
}
}
param := &traceParams{
parsed: res,
endTime: int64(1<<63 - 1),
}
if err := generateTrace(param, c); err != nil {
t.Fatalf("failed to generate ViewerData: %v", err)
}
}
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