测试 CPU Throttling 的简单程序

cpu_throttling.go

package main

import (
	"crypto/sha512"
	"flag"
	"log"
	"syscall"
	"time"
)

func main() {
	sleep := flag.Duration("sleep", time.Second, "sleep between iterations")
	iters := flag.Int("iter", 1, "work iters")

	flag.Parse()

	time.Sleep(time.Second)

	prev := usage()
	for {
		s := time.Now()
		burn(*iters)
		e := time.Now().Sub(s)

		curr := usage()
		log.Printf("burn took %dms, cpu took %dms, cpu time so far: %dms",
			ms(e), ms64(curr - prev), ms(time.Duration(curr)))
		prev = curr

		time.Sleep(*sleep)
	}
}



func ms(duration time.Duration) int {
	return ms64(duration.Nanoseconds())
}

func ms64(m int64) int {
	return int(m / 1000 / 1000)
}

func burn(iters int) {
	for i := 0; i < iters; i++ {
		sum := sha512.New()
		sum.Write([]byte("banana"))
		sum.Sum([]byte{})
	}
}

func usage() int64 {
	r := syscall.Rusage{}
	syscall.Getrusage(syscall.RUSAGE_SELF, &r)
	return r.Stime.Nano() + r.Utime.Nano()
}