Add option --relative

tcpdelay.go

@@ -18,6 +18,7 @@ var (
 
 	client        = app.Command("client", "Request measurement")
 	serverAddress = client.Arg("address", "Address:port to connect to").String()
+	relativeTimes = client.Flag("relative", "Print times relative to start").Bool()
 )
 
 func tcpdelayServer() {
@@ -56,6 +57,7 @@ func tcpdelayServer() {
 }
 
 func tcpdelayClient() {
+	t0 := time.Now().UnixNano()
 	conn, err := net.Dial("tcp", *serverAddress)
 	if err != nil {
 		log.Fatal("Cannot connect to ", *serverAddress, err)
@@ -83,7 +85,11 @@ func tcpdelayClient() {
 			log.Fatal("Unexpected offset ", oSent, " instead of ", o)
 		}
 		ts := binary.BigEndian.Uint64(buffer[16:])
-		fmt.Println(o, ts, tr) // XXX - buffer for performance
+		if *relativeTimes {
+			fmt.Println(o, int64(ts)-t0, tr-t0)
+		} else {
+			fmt.Println(o, ts, tr)
+		}
 		o += n
 	}