Buffered IO speed test of Google Go

This blog post presents the buffered IO speed test I've done with the standard implementation of the programming language Google Go, as compared to C on Linux amd64. The program I've run just copies everything from standard input to standard output, character by character using the default buffered IO. The conclusion: C (with the stdio in glibc) is about 2.68 times faster than Google Go (with its bufio).

$ cat cat.c
/* by pts@fazekas.hu at Thu Nov 12 12:04:49 CET 2009 */
#include 

int main(int argc, char **argv) {
  int c;
  while ((c = getchar()) >= 0 && putchar(c) >= 0) {}
  fflush(stdout);
  if (ferror(stdin)) {
    perror("error reading stdin");
    return 1;
  }
  if (ferror(stdout)) {
    perror("error reading stdin");
    return 1;
  }
  return 0;
}

$ cat cat.go
// by pts@fazekas.hu at Thu Nov 12 11:56:06 CET 2009
package main

import (
  "bufio";
  "os";
  "syscall";
  "unsafe";
)

func Isatty(f *os.File) bool {
  const TCGETS = 0x5401;  // Linux-specific
  var b [256]byte;
  _, _, e1 := syscall.Syscall(
      syscall.SYS_IOCTL, uintptr(f.Fd()), uintptr(TCGETS),
      uintptr(unsafe.Pointer(&b)));
  return e1 == 0;
}

func main() {
  r := bufio.NewReader(os.Stdin);
  w := bufio.NewWriter(os.Stdout);
  defer w.Flush();
  wisatty := Isatty(os.Stdout);
  for {
    c, err := r.ReadByte();
    if err == os.EOF { break }
    if err != nil { panic("error reading stdin: " + err.String()) }
    err = w.WriteByte(c);
    if err != nil { panic("error writing stdout: " + err.String()) }
    if (wisatty && c == '\n') {
      err = w.Flush();
      if err != nil { panic("error writing stdout: " + err.String()) }
    }
  }
}

Compilation and preparation:

$ gcc -s -O2 cat.c  # create a.out
$ ls -l a.out
-rwxr-xr-x 1 pts pts 4968 Nov 12 11:59 a.out
$ 6g cat.go && 6l cat.6  # create 6.out
$ ls -l 6.out
-rwxr-xr-x 1 pts pts 325257 Nov 12 11:55 6.out
$ dd if=/dev/urandom of=/tmp/data bs=1M count=256
$ time ./6.out /dev/null  # median of multiple runs
./6.out < /tmp/data > /dev/null  15.31s user 0.16s system 99% cpu 15.497 total
$ time ./6.out /dev/null  # median of multiple runs
./a.out < /tmp/data > /dev/null  5.92s user 0.20s system 99% cpu 6.153 total

Update: My naive implementation of zcat (gzip decompressor) in Google Go is only about 2.42 times slower than the C implementation (gcc -O3), and the C implementation is about 5.2 times slower than zcat(1).