mirror of
https://github.com/golang/go
synced 2024-11-05 17:46:16 -07:00
53fd522c0d
Follows suit with https://go-review.googlesource.com/#/c/20111. Generated by running $ grep -R 'Go Authors. All' * | cut -d":" -f1 | while read F;do perl -pi -e 's/Go Authors. All/Go Authors. All/g' $F;done The code in cmd/internal/unvendor wasn't changed. Fixes #15213 Change-Id: I4f235cee0a62ec435f9e8540a1ec08ae03b1a75f Reviewed-on: https://go-review.googlesource.com/21819 Reviewed-by: Ian Lance Taylor <iant@golang.org> Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
71 lines
1.5 KiB
Go
71 lines
1.5 KiB
Go
// run
|
|
|
|
// Copyright 2015 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"
|
|
)
|
|
|
|
const N = 100000
|
|
|
|
func main() {
|
|
// Allocate more Ps than processors. This raises
|
|
// the chance that we get interrupted by the OS
|
|
// in exactly the right (wrong!) place.
|
|
p := runtime.NumCPU()
|
|
runtime.GOMAXPROCS(2 * p)
|
|
|
|
// Allocate some pointers.
|
|
ptrs := make([]*int, p)
|
|
for i := 0; i < p; i++ {
|
|
ptrs[i] = new(int)
|
|
}
|
|
|
|
// Arena where we read and write pointers like crazy.
|
|
collider := make([]*int, p)
|
|
|
|
done := make(chan struct{}, 2*p)
|
|
|
|
// Start writers. They alternately write a pointer
|
|
// and nil to a slot in the collider.
|
|
for i := 0; i < p; i++ {
|
|
i := i
|
|
go func() {
|
|
for j := 0; j < N; j++ {
|
|
// Write a pointer using memmove.
|
|
copy(collider[i:i+1], ptrs[i:i+1])
|
|
// Write nil using memclr.
|
|
// (This is a magic loop that gets lowered to memclr.)
|
|
r := collider[i : i+1]
|
|
for k := range r {
|
|
r[k] = nil
|
|
}
|
|
}
|
|
done <- struct{}{}
|
|
}()
|
|
}
|
|
// Start readers. They read pointers from slots
|
|
// and make sure they are valid.
|
|
for i := 0; i < p; i++ {
|
|
i := i
|
|
go func() {
|
|
for j := 0; j < N; j++ {
|
|
var ptr [1]*int
|
|
copy(ptr[:], collider[i:i+1])
|
|
if ptr[0] != nil && ptr[0] != ptrs[i] {
|
|
panic(fmt.Sprintf("bad pointer read %p!", ptr[0]))
|
|
}
|
|
}
|
|
done <- struct{}{}
|
|
}()
|
|
}
|
|
for i := 0; i < 2*p; i++ {
|
|
<-done
|
|
}
|
|
}
|