Gecko [ 167.86.127.34 ]

Name	Size	Permission
abort.go	449 B	-rw-r--r--
badtraceback.go	1.07 KB	-rw-r--r--
checkptr.go	982 B	-rw-r--r--
crash.go	1.09 KB	-rw-r--r--
deadlock.go	5.93 KB	-rw-r--r--
gc.go	8.62 KB	-rw-r--r--
lockosthread.go	6.53 KB	-rw-r--r--
main.go	651 B	-rw-r--r--
map.go	1.26 KB	-rw-r--r--
memprof.go	884 B	-rw-r--r--
misc.go	306 B	-rw-r--r--
numcpu_freebsd.go	3.24 KB	-rw-r--r--
panicrace.go	414 B	-rw-r--r--
preempt.go	1.42 KB	-rw-r--r--
signal.go	831 B	-rw-r--r--
sleep.go	314 B	-rw-r--r--
stringconcat.go	443 B	-rw-r--r--
syscall_windows.go	1.37 KB	-rw-r--r--
syscalls.go	256 B	-rw-r--r--
syscalls_linux.go	1.27 KB	-rw-r--r--
syscalls_none.go	437 B	-rw-r--r--
timeprof.go	828 B	-rw-r--r--
traceback_ancestors.go	2.13 KB	-rw-r--r--
vdso.go	1019 B	-rw-r--r--

Code Editor : preempt.go

// Copyright 2019 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 (
	"runtime"
	"runtime/debug"
	"sync/atomic"
)

func init() {
	register("AsyncPreempt", AsyncPreempt)
}

func AsyncPreempt() {
	// Run with just 1 GOMAXPROCS so the runtime is required to
	// use scheduler preemption.
	runtime.GOMAXPROCS(1)
	// Disable GC so we have complete control of what we're testing.
	debug.SetGCPercent(-1)

// Start a goroutine with no sync safe-points.
	var ready, ready2 uint32
	go func() {
		for {
			atomic.StoreUint32(&ready, 1)
			dummy()
			dummy()
		}
	}()
	// Also start one with a frameless function.
	// This is an especially interesting case for
	// LR machines.
	go func() {
		atomic.AddUint32(&ready2, 1)
		frameless()
	}()
	// Also test empty infinite loop.
	go func() {
		atomic.AddUint32(&ready2, 1)
		for {
		}
	}()

// Wait for the goroutine to stop passing through sync
	// safe-points.
	for atomic.LoadUint32(&ready) == 0 || atomic.LoadUint32(&ready2) < 2 {
		runtime.Gosched()
	}

// Run a GC, which will have to stop the goroutine for STW and
	// for stack scanning. If this doesn't work, the test will
	// deadlock and timeout.
	runtime.GC()

println("OK")
}

//go:noinline
func frameless() {
	for i := int64(0); i < 1<<62; i++ {
		out += i * i * i * i * i * 12345
	}
}

var out int64

//go:noinline
func dummy() {}

${this.title}

Code Editor : preempt.go