from http://eng.42go.com/scala-vs-go-tcp-benchmark/

client.go

package main

import (
    "net"
    "fmt"
    "runtime"
    "sync"
    "time"
)

func ping(times int, wg *sync.WaitGroup) {
  tcpAddr, _ := net.ResolveTCPAddr("tcp4", "localhost:1201")
	conn, _ := net.DialTCP("tcp", nil, tcpAddr)

	for i := 0; i < times; i++ {
		_, _ = conn.Write([]byte("Ping"))
		var buf [4]byte
		_, _ = conn.Read(buf[0:])
	}

	wg.Done()
	conn.Close()
}

func main() {
	runtime.GOMAXPROCS(8)

	totalPing := 1000000
	concurrentConnection := 10
	pingsPerConnection := totalPing / concurrentConnection
	actualTotalPings := pingsPerConnection *concurrentConnection

	var wg sync.WaitGroup

	start := time.Now()

	for i:=0; i<concurrentConnection; i++ {
		wg.Add(1)
		go ping(pingsPerConnection, &wg)
	}
	wg.Wait()

	elapsed := 1000000 * time.Since(start).Seconds()

	fmt.Println(elapsed / float64(actualTotalPings))
}

server.go

package main

import (
  "net"
	"runtime"
)

func handleClient(conn net.Conn) {
	defer conn.Close()

	var buf [4]byte

	for {
		n, err := conn.Read(buf[0:])

		if err != nil {return}

		if n > 0 {
			_, err :=  conn.Write([]byte("Pong"))

			if err != nil {return}
		}
	}
}

func main() {
	runtime.GOMAXPROCS(8)

	tcpAddr, _ := net.ResolveTCPAddr("tcp4", ":1201")
	listener, _ := net.ListenTCP("tcp", tcpAddr)

	for {
		conn, _ := listener.Accept()
		go handleClient(conn)
	}
}