socketpair.go

package main

import (
	"io"
	"io/ioutil"
	"log"
	"net"
	"os"
	"syscall"
	"time"
)

const MB = 1024 * 1024

func socketPairUnix(typ int) (*net.UnixConn, *net.UnixConn) {
	fds, err := syscall.Socketpair(syscall.AF_UNIX, typ, 0)
	if err != nil {
		panic(os.NewSyscallError("socketpair", err))
	}
	file := os.NewFile(uintptr(fds[0]), "")
	conn0, err := net.FileConn(file)
	if err != nil {
		panic(err)
	}
	if err := file.Close(); err != nil {
		panic(err)
	}
	file = os.NewFile(uintptr(fds[1]), "")
	conn1, err := net.FileConn(file)
	if err != nil {
		panic(err)
	}
	if err := file.Close(); err != nil {
		panic(err)
	}
	return conn0.(*net.UnixConn), conn1.(*net.UnixConn)
}

func main() {
	left, right := socketPairUnix(syscall.SOCK_STREAM)
	doneChan := make(chan struct{})
	go func(r io.ReadCloser, doneChan chan struct{}) {
		defer r.Close()
		_, err := io.Copy(ioutil.Discard, r)
		if err != nil {
			log.Fatalf("ERR: %v", err)
		}
		doneChan <- struct{}{}
	}(right, doneChan)

	start := time.Now()
	nwritten := 0
	for i := 0; i < 1000; i++ {
		buf := make([]byte, 64*1024)
		n, _ := left.Write(buf)
		nwritten += n
	}
	left.Close()
	delta := time.Now().Sub(start)
	mbs := float64(nwritten) / MB
	log.Printf("[W]: %d(b) %d(ms) %f(MB/s)", nwritten, delta.Milliseconds(), mbs/delta.Seconds())

	<-doneChan
}