package main

import (
	"os"
	"fmt"
)

func main() {
	filename := "go.txt"
	os.Remove(filename)
	fp, err := os.OpenFile(filename, os.O_CREATE | os.O_APPEND | os.O_WRONLY, 0644)
	if err != nil {
		panic(err)
	}
	count := 1000
	for i:=0; i<count; i++ {
		var err error
		s := fmt.Sprintf("%010d\n", i)
		_, err = fp.WriteString(s)
		if err != nil {
			panic(err)
		}
		err = fp.Sync()
		if err != nil {
			panic(err)
		}
	}
	fp.Close()

	fmt.Printf("%d fsync\n", count)
}

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>

int main(int argc, char** argv) {
	const char *filename = "c.txt";
	if(unlink(filename) != 0 && errno != ENOENT){
		printf("%d error: %s\n", __LINE__, strerror(errno));
		exit(1);
	}
	int fd = open(filename, O_CREAT | O_WRONLY | O_APPEND, 0644);
	if(fd == -1){
		printf("%d error: %s\n", __LINE__, strerror(errno));
		exit(1);
	}

	int SIZE = 1000;

	for(int i=0; i<SIZE; i++){
		char buf[16];
		snprintf(buf, sizeof(buf), "%010d\n", i);

		int ret;
		ret = write(fd, buf, strlen(buf));
		if(ret == -1){
			printf("%d error: %s\n", __LINE__, strerror(errno));
			exit(1);
		}
		ret = fsync(fd);
		if(ret == -1){
			printf("%d error: %s\n", __LINE__, strerror(errno));
			exit(1);
		}
	}

	printf("%d fync\n", SIZE);

	return 0;
}

$ go build bench-fsync.go
$ time ./bench-fsync 
1000 fsync

real	0m22.768s
user	0m0.405s
sys	0m0.808s

$ time ./bench-fsync 
1000 fsync

real	0m22.297s
user	0m0.159s
sys	0m0.571s

$ gcc -O2 bench-fsync.c 
$ time ./a.out 
1000 fync

real	0m0.580s
user	0m0.003s
sys	0m0.022s

$ time ./a.out 
1000 fync

real	0m0.074s
user	0m0.004s
sys	0m0.030s