consume cpu at specified percent

usecpu.go

package main

import (
	"flag"
	"log"
	"runtime"
	"strconv"
	"time"
)

func loop(c <-chan bool) {
	_, ok := <-c // start
	if !ok {
		return
	}
	i := 0 // to work under go1.1.2
	for {
		select {
		case _, ok = <-c:
			if !ok {
				return
			}
			_, ok = <-c
			if !ok {
				return
			}
		default:
			// to work under go1.1.2
			i++
			if i % 10000 == 0 {
				runtime.Gosched()
				i = 0
			}
		}
	}
}

func main() {
	flag.Parse()
	percent, err := strconv.Atoi(flag.Arg(0))
	if err != nil {
		log.Fatal(err)
	}
	c := make(chan bool)
	go loop(c)
	unit := int(time.Second)
	for {
		c <- true
		time.Sleep(time.Duration(unit * percent / 100))
		c <- true
		time.Sleep(time.Duration(unit * (100 - percent) / 100))
	}
	close(c)
}