dumb iops

main.go

package main

import (
	"flag"
	"fmt"
	"os"
	"runtime"
	"sync/atomic"
	"syscall"
	"time"
)

var (
	goroutines = flag.Int("goroutines", 32, "goroutines")
)

func main() {
	flag.Parse()
	runtime.GOMAXPROCS(2 * *goroutines)

	var count int32

	for i := 0; i < *goroutines; i++ {
		go func(i int) {
			fn := fmt.Sprintf("testfile-%d", i)
			f, _ := os.Create(fn)
			j := 0
			for {
				f.Seek(0, 0)
				fmt.Fprintln(f, j)
				syscall.Fdatasync(int(f.Fd()))
				j++
				atomic.AddInt32(&count, 1)
			}
		}(i)
	}

	var old int32
	tick := time.Tick(time.Second)
	for {
		<-tick
		new := atomic.LoadInt32(&count)
		fmt.Println(new - old)
		old = new
	}
}