Fsync Benchmarking for Go

fsycn.go

package main

import (
	"flag"
	"io/ioutil"
	"log"
	"os"
	"time"
)

var iterations = flag.Int("n", 100, "iterations to test")

func main() {
	flag.Parse()
	out, err := ioutil.TempFile("", "fsync")
	if err != nil {
		log.Fatal(err)
	}
	defer out.Close()
	defer os.Remove(out.Name())

	buffer := []byte{'A'}
	N := *iterations
	duration := time.Duration(0)
	for i := 0; i < N; i++ {
		_, err = out.Write(buffer)
		if err != nil {
			log.Fatal(err)
		}
		start := time.Now()
		err = out.Sync()
		end := time.Now()
		duration += end.Sub(start)
		if err != nil {
			log.Fatal(err)
		}
	}

	log.Printf("Time taken %s for %d fsyncs", duration, N)
	log.Printf("Time taken %s per fsync", duration/time.Duration(N))
}