mirror of
https://github.com/golang/go
synced 2024-11-18 07:04:52 -07:00
11b283092a
Added a flag to generic and various architectures' atomic operations that are judged to have observable side effects and thus cannot be dead-code-eliminated. Test requires GOMAXPROCS > 1 without preemption in loop. Fixes #19182. Change-Id: Id2230031abd2cca0bbb32fd68fc8a58fb912070f Reviewed-on: https://go-review.googlesource.com/37333 Run-TryBot: David Chase <drchase@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com>
37 lines
710 B
Go
37 lines
710 B
Go
// run
|
|
|
|
// 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.
|
|
|
|
package main
|
|
|
|
import (
|
|
"fmt"
|
|
"runtime"
|
|
"sync/atomic"
|
|
"time"
|
|
)
|
|
|
|
var a uint64 = 0
|
|
|
|
func main() {
|
|
runtime.GOMAXPROCS(2) // With just 1, infinite loop never yields
|
|
|
|
go func() {
|
|
for {
|
|
atomic.AddUint64(&a, uint64(1))
|
|
}
|
|
}()
|
|
|
|
time.Sleep(10 * time.Millisecond) // Short sleep is enough in passing case
|
|
i, val := 0, atomic.LoadUint64(&a)
|
|
for ; val == 0 && i < 100; val, i = atomic.LoadUint64(&a), i+1 {
|
|
time.Sleep(100 * time.Millisecond)
|
|
}
|
|
if val == 0 {
|
|
fmt.Printf("Failed to observe atomic increment after %d tries\n", i)
|
|
}
|
|
|
|
}
|