diff --git a/examples/websocket/nbioclient/client.go b/examples/websocket/nbioclient/client.go
index 90f8468e..7c5f131e 100644
--- a/examples/websocket/nbioclient/client.go
+++ b/examples/websocket/nbioclient/client.go
@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"flag"
 	"fmt"
 	"log"
 	"net/url"
@@ -13,24 +14,38 @@ import (
 	"github.com/lesismal/nbio/nbhttp/websocket"
 )
 
-func newUpgrader() *websocket.Upgrader {
+var (
+	disableEcho = flag.Bool("disable-echo", true, "diable echo incoming message")
+	verbose     = flag.Bool("verbose", false, "verbose mode")
+	connections = flag.Int("connections", 1000, "number of connecions")
+	msgSize     = flag.Int("msg-size", 1*1024*1024, "message size")
+)
+
+func newUpgrader(connectedChannel *chan *websocket.Conn) *websocket.Upgrader {
 	u := websocket.NewUpgrader()
 	u.OnMessage(func(c *websocket.Conn, messageType websocket.MessageType, data []byte) {
 		// echo
-		time.AfterFunc(time.Second, func() {
-			c.WriteMessage(messageType, data)
-		})
-		log.Println("onEcho:", string(data))
+		if !*disableEcho {
+			time.AfterFunc(time.Second, func() {
+				c.WriteMessage(messageType, data)
+			})
+			log.Println("onEcho:", string(data))
+		}
+		if *verbose {
+			log.Println("received ack:", string(data))
+		}
+		*connectedChannel <- c
 	})
-
 	u.OnClose(func(c *websocket.Conn, err error) {
-		fmt.Println("OnClose:", c.RemoteAddr().String(), err)
+		if *verbose {
+			fmt.Println("OnClose:", c.RemoteAddr().String(), err)
+		}
 	})
-
 	return u
 }
 
 func main() {
+	flag.Parse()
 	engine := nbhttp.NewEngine(nbhttp.Config{
 		SupportClient: true,
 	})
@@ -40,24 +55,50 @@ func main() {
 		return
 	}
 
-	for i := 0; i < 1; i++ {
+	connectionChannels := make(chan *websocket.Conn, *connections)
+	for i := 0; i < *connections; i++ {
 		u := url.URL{Scheme: "ws", Host: "localhost:8888", Path: "/ws"}
 		dialer := &websocket.Dialer{
 			Engine:      engine,
-			Upgrader:    newUpgrader(),
+			Upgrader:    newUpgrader(&connectionChannels),
 			DialTimeout: time.Second * 3,
 		}
 		c, _, err := dialer.Dial(u.String(), nil)
 		if err != nil {
 			panic(fmt.Errorf("dial: %v", err))
 		}
-		c.WriteMessage(websocket.TextMessage, []byte("hello"))
+		connectionChannels <- c
+	}
+	output := make([]byte, *msgSize, *msgSize)
+	ctx, cancel := context.WithCancel(context.Background())
+	for i := 0; i < 10; i++ {
+		go func() {
+			defer func() {
+				if *verbose {
+					log.Println("sender routine exited")
+				}
+			}()
+			for {
+				select {
+				case c := <-connectionChannels:
+					time.Sleep(1000)
+					if *verbose {
+						log.Println("sending message")
+					}
+					c.WriteMessage(websocket.BinaryMessage, output)
+					if *verbose {
+						log.Println("done sending message")
+					}
+				case <-ctx.Done():
+					log.Println("ctx done")
+					return
+				}
+			}
+		}()
 	}
-
 	interrupt := make(chan os.Signal, 1)
 	signal.Notify(interrupt, os.Interrupt)
 	<-interrupt
-	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
 	defer cancel()
 	engine.Shutdown(ctx)
 }
diff --git a/examples/websocket/server/server.go b/examples/websocket/server/server.go
index 1929f87a..b06c2fb5 100644
--- a/examples/websocket/server/server.go
+++ b/examples/websocket/server/server.go
@@ -7,30 +7,60 @@ import (
 	"net/http"
 	"os"
 	"os/signal"
+	"sync/atomic"
 	"time"
 
+	"github.com/pkg/profile"
 	"github.com/lesismal/nbio/nbhttp"
 	"github.com/lesismal/nbio/nbhttp/websocket"
 )
 
-var onDataFrame = flag.Bool("UseOnDataFrame", false, "Server will use OnDataFrame api instead of OnMessage")
+var (
+	onDataFrame = flag.Bool("UseOnDataFrame", false, "Server will use OnDataFrame api instead of OnMessage")
+	disableEcho = flag.Bool("disable-echo", false, "disable echo")
+	verbose     = flag.Bool("verbose", false, "verbose mode")
+	ack 		= flag.Bool("ack", true, "send back an acknowledgement")
+
+	connections   uint64
+	msgReceived   uint64
+	bytesReceived uint64
+)
 
 func newUpgrader() *websocket.Upgrader {
 	u := websocket.NewUpgrader()
+	u.OnOpen(func(c *websocket.Conn) {
+		atomic.AddUint64(&connections, 1)
+	})
 	if *onDataFrame {
 		u.OnDataFrame(func(c *websocket.Conn, messageType websocket.MessageType, fin bool, data []byte) {
 			// echo
-			c.WriteFrame(messageType, true, fin, data)
+			if !*disableEcho {
+				c.WriteFrame(messageType, true, fin, data)
+			}
+			atomic.AddUint64(&bytesReceived, uint64(len(data)))
+			if fin {
+				atomic.AddUint64(&msgReceived, 1)
+			}
 		})
 	} else {
 		u.OnMessage(func(c *websocket.Conn, messageType websocket.MessageType, data []byte) {
 			// echo
-			c.WriteMessage(messageType, data)
+			if !*disableEcho {
+				c.WriteMessage(messageType, data)
+			}
+			atomic.AddUint64(&bytesReceived, uint64(len(data)))
+			atomic.AddUint64(&msgReceived, 1)
+			if *ack {
+				c.WriteMessage(messageType, []byte("a"))
+			}
 		})
 	}
 
 	u.OnClose(func(c *websocket.Conn, err error) {
-		fmt.Println("OnClose:", c.RemoteAddr().String(), err)
+		if *verbose {
+			fmt.Println("OnClose:", c.RemoteAddr().String(), err)
+		}
+		atomic.AddUint64(&connections, ^uint64(0))
 	})
 	return u
 }
@@ -44,7 +74,9 @@ func onWebsocket(w http.ResponseWriter, r *http.Request) {
 	}
 	wsConn := conn.(*websocket.Conn)
 	wsConn.SetReadDeadline(time.Time{})
-	fmt.Println("OnOpen:", wsConn.RemoteAddr().String())
+	if *verbose {
+		fmt.Println("OnOpen:", wsConn.RemoteAddr().String())
+	}
 }
 
 func main() {
@@ -57,11 +89,24 @@ func main() {
 		Addrs:   []string{"localhost:8888"},
 	}, mux, nil)
 
+	defer profile.Start(profile.MemProfile).Stop()
+
 	err := svr.Start()
 	if err != nil {
 		fmt.Printf("nbio.Start failed: %v\n", err)
 		return
 	}
+	go func() {
+		ticker := time.NewTicker(time.Second * 5)
+		for {
+			select {
+			case <-ticker.C:
+				fmt.Printf("connection %d data received %d\n", atomic.LoadUint64(&connections), atomic.LoadUint64(&bytesReceived))
+			}
+
+		}
+
+	}()
 
 	interrupt := make(chan os.Signal, 1)
 	signal.Notify(interrupt, os.Interrupt)
diff --git a/go.mod b/go.mod
index eaac9562..ae5c4160 100644
--- a/go.mod
+++ b/go.mod
@@ -5,4 +5,5 @@ go 1.16
 require (
 	github.com/gorilla/websocket v1.4.2
 	github.com/lesismal/llib v1.1.0
+	github.com/pkg/profile v1.6.0 // indirect
 )
diff --git a/go.sum b/go.sum
index 07d0f655..2ae99adf 100644
--- a/go.sum
+++ b/go.sum
@@ -4,6 +4,8 @@ github.com/gorilla/websocket v1.4.2 h1:+/TMaTYc4QFitKJxsQ7Yye35DkWvkdLcvGKqM+x0U
 github.com/gorilla/websocket v1.4.2/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
 github.com/lesismal/llib v1.1.0 h1:dpU21CcgQXyY9GW/ibLZhXf46Lst+Y4KhWO5R34FAWk=
 github.com/lesismal/llib v1.1.0/go.mod h1:3vmCrIMrpkaoA3bDu/sI+J7EyEUMPbOvmAxb7PlzilM=
+github.com/pkg/profile v1.6.0 h1:hUDfIISABYI59DyeB3OTay/HxSRwTQ8rB/H83k6r5dM=
+github.com/pkg/profile v1.6.0/go.mod h1:qBsxPvzyUincmltOk6iyRVxHYg4adc0OFOv72ZdLa18=
 github.com/spaolacci/murmur3 v0.0.0-20180118202830-f09979ecbc72/go.mod h1:JwIasOWyU6f++ZhiEuf87xNszmSA2myDM2Kzu9HwQUA=
 golang.org/x/crypto v0.0.0-20210513122933-cd7d49e622d5 h1:N6Jp/LCiEoIBX56BZSR2bepK5GtbSC2DDOYT742mMfE=
 golang.org/x/crypto v0.0.0-20210513122933-cd7d49e622d5/go.mod h1:P+XmwS30IXTQdn5tA2iutPOUgjI07+tq3H3K9MVA1s8=
diff --git a/nbhttp/websocket/upgrader.go b/nbhttp/websocket/upgrader.go
index aa682bb7..9facc7c6 100644
--- a/nbhttp/websocket/upgrader.go
+++ b/nbhttp/websocket/upgrader.go
@@ -315,6 +315,14 @@ func (u *Upgrader) validFrame(opcode MessageType, fin, res1, res2, res3, expecti
 	return nil
 }
 
+func readAppend(a, b []byte) []byte {
+	return append(a, b...)	
+}
+
+func messageAppend(a, b []byte) []byte {
+	return append(a, b...)	
+}
+
 // Read .
 func (u *Upgrader) Read(p *nbhttp.Parser, data []byte) error {
 	bufLen := len(u.buffer)
@@ -326,7 +334,7 @@ func (u *Upgrader) Read(p *nbhttp.Parser, data []byte) error {
 	if bufLen == 0 {
 		u.buffer = data
 	} else {
-		u.buffer = append(u.buffer, data...)
+		u.buffer = readAppend(u.buffer, data)
 		oldBuffer = u.buffer
 	}
 
@@ -362,7 +370,7 @@ func (u *Upgrader) Read(p *nbhttp.Parser, data []byte) error {
 					u.message = mempool.Malloc(len(body))
 					copy(u.message, body)
 				} else {
-					u.message = append(u.message, body...)
+					u.message = messageAppend(u.message, body)
 				}
 			}
 			if fin {
@@ -447,6 +455,7 @@ func (u *Upgrader) handleMessage(p *nbhttp.Parser, opcode MessageType, body []by
 
 	p.Execute(func() {
 		u.handleWsMessage(u.conn, opcode, body)
+		mempool.Free(body)
 	})
 
 }