diff --git a/endpoint/motanCommonEndpoint.go b/endpoint/motanCommonEndpoint.go
index 8f6a87a0..be0bfa91 100644
--- a/endpoint/motanCommonEndpoint.go
+++ b/endpoint/motanCommonEndpoint.go
@@ -37,7 +37,7 @@ type MotanCommonEndpoint struct {
 	channels                     *ChannelPool
 	destroyed                    bool
 	destroyCh                    chan struct{}
-	available                    bool
+	available                    atomic.Value
 	errorCount                   uint32
 	proxy                        bool
 	errorCountThreshold          int64
@@ -68,7 +68,7 @@ func (m *MotanCommonEndpoint) GetRuntimeInfo() map[string]interface{} {
 }
 
 func (m *MotanCommonEndpoint) setAvailable(available bool) {
-	m.available = available
+	m.available.Store(available)
 }
 
 func (m *MotanCommonEndpoint) SetSerialization(s motan.Serialization) {
@@ -306,7 +306,9 @@ func (m *MotanCommonEndpoint) keepalive() {
 			if atomic.LoadUint32(&m.keepaliveType) == KeepaliveProfile {
 				m.profile()
 			} else {
-				m.heartbeat()
+				if m.heartbeat() {
+					return
+				}
 			}
 		case <-m.destroyCh:
 			return
@@ -314,7 +316,7 @@ func (m *MotanCommonEndpoint) keepalive() {
 	}
 }
 
-func (m *MotanCommonEndpoint) heartbeat() {
+func (m *MotanCommonEndpoint) heartbeat() bool {
 	if channel, err := m.channels.Get(); err != nil {
 		vlog.Infof("[keepalive] failed. url:%s, err:%s", m.url.GetIdentity(), err.Error())
 	} else {
@@ -323,10 +325,11 @@ func (m *MotanCommonEndpoint) heartbeat() {
 			m.setAvailable(true)
 			m.resetErr()
 			vlog.Infof("[keepalive] heartbeat success. url: %s", m.url.GetIdentity())
-			return
+			return true
 		}
 		vlog.Infof("[keepalive] heartbeat failed. url:%s, err:%s", m.url.GetIdentity(), err.Error())
 	}
+	return false
 }
 
 func (m *MotanCommonEndpoint) profile() {
@@ -357,7 +360,7 @@ func (m *MotanCommonEndpoint) SetURL(url *motan.URL) {
 }
 
 func (m *MotanCommonEndpoint) IsAvailable() bool {
-	return m.available
+	return m.available.Load().(bool)
 }
 
 type Channel struct {
diff --git a/endpoint/motanCommonEndpoint_test.go b/endpoint/motanCommonEndpoint_test.go
index 47d97540..edb70c98 100644
--- a/endpoint/motanCommonEndpoint_test.go
+++ b/endpoint/motanCommonEndpoint_test.go
@@ -8,6 +8,7 @@ import (
 	"github.com/weibocom/motan-go/serialize"
 	"net"
 	"runtime"
+	"strconv"
 	"sync/atomic"
 	"testing"
 	"time"
@@ -55,9 +56,10 @@ func TestV1RecordErrEmptyThreshold(t *testing.T) {
 }
 
 func TestV1RecordErrWithErrThreshold(t *testing.T) {
+	errorCountThreshold := 5
 	url := &motan.URL{Port: 8989, Protocol: "motan"}
-	url.PutParam(motan.TimeOutKey, "100")
-	url.PutParam(motan.ErrorCountThresholdKey, "5")
+	url.PutParam(motan.TimeOutKey, "1100")
+	url.PutParam(motan.ErrorCountThresholdKey, strconv.Itoa(errorCountThreshold))
 	url.PutParam(motan.ClientConnectionKey, "1")
 	url.PutParam(motan.AsyncInitConnection, "false")
 	ep := &MotanCommonEndpoint{}
@@ -66,15 +68,25 @@ func TestV1RecordErrWithErrThreshold(t *testing.T) {
 	ep.SetSerialization(&serialize.SimpleSerialization{})
 	ep.Initialize()
 	assert.Equal(t, 1, ep.clientConnection)
-	for j := 0; j < 10; j++ {
+	for j := 0; j < errorCountThreshold; j++ {
 		request := &motan.MotanRequest{ServiceName: "test", Method: "test"}
 		request.Attachment = motan.NewStringMap(0)
-		ep.Call(request)
-		if j < 4 {
+		request.Attachment.Store("exception", "other_exception")
+		request.Attachment.Store("sleep_time", "200")
+		resp := ep.Call(request)
+		assert.NotNil(t, resp)
+		assert.NotNil(t, resp.GetException())
+		assert.Equal(t, motan.EUnkonwnMsg, resp.GetException().ErrCode)
+		if j < errorCountThreshold-1 {
 			assert.True(t, ep.IsAvailable())
 		} else {
-			assert.False(t, ep.IsAvailable())
 			assert.Equal(t, KeepaliveHeartbeat, atomic.LoadUint32(&ep.keepaliveType))
+			// wait keepalive goroutine set keepaliveRunning status
+			time.Sleep(time.Millisecond * 100)
+			assert.True(t, ep.keepaliveRunning.Load().(bool))
+			time.Sleep(ep.keepaliveInterval * 2)
+			assert.True(t, ep.IsAvailable())
+			assert.False(t, ep.keepaliveRunning.Load().(bool))
 		}
 	}
 	<-ep.channels.channels
@@ -90,7 +102,7 @@ func TestV1RecordErrWithErrThreshold(t *testing.T) {
 
 func TestNotFoundProviderCircuitBreaker(t *testing.T) {
 	url := &motan.URL{Port: 8989, Protocol: "motan"}
-	url.PutParam(motan.TimeOutKey, "2000")
+	url.PutParam(motan.TimeOutKey, "1200")
 	url.PutParam(motan.ErrorCountThresholdKey, "5")
 	url.PutParam(motan.ClientConnectionKey, "10")
 	url.PutParam(motan.AsyncInitConnection, "false")
diff --git a/endpoint/motanEndpoint_test.go b/endpoint/motanEndpoint_test.go
index 3897a9fa..545a0d88 100644
--- a/endpoint/motanEndpoint_test.go
+++ b/endpoint/motanEndpoint_test.go
@@ -319,15 +319,17 @@ func handle(netListen net.Listener) {
 }
 
 func handleConnection(conn net.Conn, timeout int) {
-	reader := bufio.NewReader(conn)
-	decodeBuf := make([]byte, 100)
-	msg, err := protocol.Decode(reader, &decodeBuf)
-	if err != nil {
-		time.Sleep(time.Millisecond * 1000)
-		conn.Close()
-		return
+	for {
+		reader := bufio.NewReader(conn)
+		decodeBuf := make([]byte, 100)
+		msg, err := protocol.Decode(reader, &decodeBuf)
+		if err != nil {
+			time.Sleep(time.Millisecond * 1000)
+			conn.Close()
+			return
+		}
+		processMsg(msg, conn)
 	}
-	processMsg(msg, conn)
 }
 
 func processMsg(msg *protocol.Message, conn net.Conn) {
@@ -342,7 +344,12 @@ func processMsg(msg *protocol.Message, conn net.Conn) {
 	if msg.Header.IsHeartbeat() {
 		res = protocol.BuildHeartbeat(msg.Header.RequestID, protocol.Res)
 	} else {
-		time.Sleep(time.Millisecond * 1000)
+		sleepTimeStr, _ := msg.Metadata.Load("sleep_time")
+		sleepTimeValue, _ := strconv.Atoi(sleepTimeStr)
+		if sleepTimeValue <= 0 {
+			sleepTimeValue = 1000
+		}
+		time.Sleep(time.Millisecond * time.Duration(sleepTimeValue))
 		var resp *motan.MotanResponse
 		e, _ := msg.Metadata.Load("exception")
 		switch e {
@@ -352,6 +359,12 @@ func processMsg(msg *protocol.Message, conn net.Conn) {
 					ErrCode: motan.EProviderNotExist,
 					ErrMsg:  motan.ProviderNotExistPrefix,
 					ErrType: motan.ServiceException})
+		case "other_exception":
+			resp = motan.BuildExceptionResponse(lastRequestID,
+				&motan.Exception{
+					ErrCode: motan.EUnkonwnMsg,
+					ErrMsg:  "exception",
+					ErrType: motan.ServiceException})
 		default:
 			resp = &motan.MotanResponse{
 				RequestID:   lastRequestID,