stress.go

package main

import (
	"fmt"
	"io/ioutil"
	"os"
	"regexp"
	"strconv"
	"strings"
	"time"
)

func stress(i int) {
	f, _ := os.Create(fmt.Sprintf("file%d", i))

	i = 0
	for {
		f.Seek(0, 0)
		fmt.Fprintf(f, "%d", i)
		f.Sync()
		i++
	}
}

var r = regexp.MustCompile(`\s+`)

func main() {
	j, _ := strconv.Atoi(os.Args[1])

	for i := 0; i < j; i++ {
		go stress(i)
	}

	t := time.Tick(time.Second)
	start := time.Now()
	startios := 0
	for {
		b, _ := ioutil.ReadFile(fmt.Sprintf("/sys/block/%s/stat", os.Args[2]))

		fields := r.Split(strings.TrimSpace(string(b)), -1)
		ios, _ := strconv.Atoi(fields[4])
		if startios == 0 {
			startios = ios
		} else {
			fmt.Println((ios - startios) / int(time.Now().Sub(start)/time.Second))
		}

		<-t
	}
}