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https://github.com/golang/go
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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
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// Copyright 2017 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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package main
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import (
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"fmt"
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"runtime"
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"sync/atomic"
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"time"
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)
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var a uint64 = 0
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func main() {
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runtime.GOMAXPROCS(2) // With just 1, infinite loop never yields
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go func() {
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for {
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atomic.AddUint64(&a, uint64(1))
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}
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}()
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time.Sleep(10 * time.Millisecond) // Short sleep is enough in passing case
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i, val := 0, atomic.LoadUint64(&a)
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for ; val == 0 && i < 100; val, i = atomic.LoadUint64(&a), i+1 {
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time.Sleep(100 * time.Millisecond)
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}
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if val == 0 {
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fmt.Printf("Failed to observe atomic increment after %d tries\n", i)
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}
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}
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