Public
Snippet $263 authored by Kirill Smelkov

cpuburn.go (burn all cores with more insn/cycle than tradidional cpuburn)

cpuburn.go
// Copyright (C) 2017  Nexedi SA and Contributors.
//                     Kirill Smelkov <kirr@nexedi.com>
//
// This program is free software: you can Use, Study, Modify and Redistribute
// it under the terms of the GNU General Public License version 3, or (at your
// option) any later version, as published by the Free Software Foundation.
//
// You can also Link and Combine this program with other software covered by
// the terms of any of the Free Software licenses or any of the Open Source
// Initiative approved licenses and Convey the resulting work. Corresponding
// source of such a combination shall include the source code for all other
// software used.
//
// This program is distributed WITHOUT ANY WARRANTY; without even the implied
// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
//
// See COPYING file for full licensing terms.
// See https://www.nexedi.com/licensing for rationale and options.

// cpuburn load all cpu cores
//
// reason for this program: cpuburn Debian package got bitrotted with
// recomendation to use "yes >/dev/null" instead.
package main

import (
	"runtime"
	"sync"
)

func work() {
	var i [3]int
	var x [3]float64

	i[0], i[1], i[2] = 1, 2, 3
	x[0], x[1], x[2] = 3.14, 2.17, 1.61

	for j := 0; ; j++ {
		kp := j % 3
		k := (kp+1) % 3

		x[k] += float64(i[kp]) * x[kp]
	}
}

func main() {
	wg := sync.WaitGroup{}
	njob := runtime.NumCPU()

	for i := 0; i < njob; i++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			work()
		}()
	}

	wg.Wait()
}