diff --git a/src/main/AndroidManifest.xml b/src/main/AndroidManifest.xml
index f17450ae..ad614eae 100644
--- a/src/main/AndroidManifest.xml
+++ b/src/main/AndroidManifest.xml
@@ -108,14 +108,6 @@
             </intent-filter>
         </service>
 
-        <receiver android:name=".AppManagerReceiver">
-            <intent-filter>
-                <action android:name="android.intent.action.PACKAGE_ADDED" />
-                <action android:name="android.intent.action.PACKAGE_REMOVED" />
-                <data android:scheme="package"/>
-            </intent-filter>
-        </receiver>
-
         <receiver android:name=".ShadowsocksReceiver">
             <intent-filter>
                 <action android:name="android.intent.action.BOOT_COMPLETED"/>
diff --git a/src/main/jni/shadowsocks-libev b/src/main/jni/shadowsocks-libev
index 48a063ef..68eaf3b1 160000
--- a/src/main/jni/shadowsocks-libev
+++ b/src/main/jni/shadowsocks-libev
@@ -1 +1 @@
-Subproject commit 48a063ef1e1a886e274a0fbb797e88358deca35b
+Subproject commit 68eaf3b12d385381130c046547163b81e1807ba4
diff --git a/src/main/scala/com/github/shadowsocks/AppManager.scala b/src/main/scala/com/github/shadowsocks/AppManager.scala
index 7e86eb9f..9f0d9bba 100644
--- a/src/main/scala/com/github/shadowsocks/AppManager.scala
+++ b/src/main/scala/com/github/shadowsocks/AppManager.scala
@@ -39,8 +39,11 @@
 
 package com.github.shadowsocks
 
+import java.util.concurrent.atomic.AtomicBoolean
+
+import android.Manifest.permission
+import android.content._
 import android.content.pm.PackageManager
-import android.content.{ClipData, ClipboardManager, Context}
 import android.graphics.PixelFormat
 import android.graphics.drawable.Drawable
 import android.os.{Bundle, Handler}
@@ -54,7 +57,6 @@ import android.view._
 import android.widget.AbsListView.OnScrollListener
 import android.widget.CompoundButton.OnCheckedChangeListener
 import android.widget._
-import android.Manifest.permission
 import com.github.shadowsocks.utils.{Key, Utils}
 
 import scala.collection.JavaConversions._
@@ -65,13 +67,31 @@ object AppManager {
   case class ProxiedApp(name: String, packageName: String, icon: Drawable)
   private case class ListEntry(switch: Switch, text: TextView, icon: ImageView)
 
-  var cachedApps: Array[ProxiedApp] = _
+  private var instance: AppManager = _
+
+  private var receiverRegistered: Boolean = _
+  private var cachedApps: Array[ProxiedApp] = _
   private def getApps(pm: PackageManager) = {
-    if (cachedApps == null) cachedApps = pm.getInstalledPackages(PackageManager.GET_PERMISSIONS)
-      .filter(p => p.requestedPermissions != null && p.requestedPermissions.contains(permission.INTERNET))
-      .map(p => new ProxiedApp(pm.getApplicationLabel(p.applicationInfo).toString, p.packageName,
-        p.applicationInfo.loadIcon(pm))).toArray
-    cachedApps
+    if (!receiverRegistered) {
+      val filter = new IntentFilter(Intent.ACTION_PACKAGE_ADDED)
+      filter.addAction(Intent.ACTION_PACKAGE_REMOVED)
+      filter.addDataScheme("package")
+      ShadowsocksApplication.instance.registerReceiver((context: Context, intent: Intent) =>
+        if (intent.getAction != Intent.ACTION_PACKAGE_REMOVED ||
+          !intent.getBooleanExtra(Intent.EXTRA_REPLACING, false)) {
+          synchronized(cachedApps = null)
+          val instance = AppManager.instance
+          if (instance != null) instance.reloadApps()
+        }, filter)
+      receiverRegistered = true
+    }
+    synchronized {
+      if (cachedApps == null) cachedApps = pm.getInstalledPackages(PackageManager.GET_PERMISSIONS)
+        .filter(p => p.requestedPermissions != null && p.requestedPermissions.contains(permission.INTERNET))
+        .map(p => new ProxiedApp(pm.getApplicationLabel(p.applicationInfo).toString, p.packageName,
+          p.applicationInfo.loadIcon(pm))).toArray
+      cachedApps
+    }
   }
 }
 
@@ -86,43 +106,7 @@ class AppManager extends AppCompatActivity with OnCheckedChangeListener with OnC
   private var loadingView: View = _
   private var overlay: TextView = _
   private var adapter: ListAdapter = _
-  @volatile private var appsLoading: Boolean = _
-
-  def loadApps() {
-    appsLoading = true
-    proxiedApps = ShadowsocksApplication.settings.getString(Key.proxied, "").split('\n').to[mutable.HashSet]
-    apps = getApps(getPackageManager).sortWith((a, b) => {
-      val aProxied = proxiedApps.contains(a.packageName)
-      if (aProxied ^ proxiedApps.contains(b.packageName)) aProxied else a.name.compareToIgnoreCase(b.name) < 0
-    })
-    adapter = new ArrayAdapter[ProxiedApp](this, R.layout.layout_apps_item, R.id.itemtext, apps) {
-      override def getView(position: Int, view: View, parent: ViewGroup): View = {
-        var convertView = view
-        var entry: ListEntry = null
-        if (convertView == null) {
-          convertView = getLayoutInflater.inflate(R.layout.layout_apps_item, parent, false)
-          entry = new ListEntry(convertView.findViewById(R.id.itemcheck).asInstanceOf[Switch],
-            convertView.findViewById(R.id.itemtext).asInstanceOf[TextView],
-            convertView.findViewById(R.id.itemicon).asInstanceOf[ImageView])
-          convertView.setOnClickListener(AppManager.this)
-          convertView.setTag(entry)
-          entry.switch.setOnCheckedChangeListener(AppManager.this)
-        } else {
-          entry = convertView.getTag.asInstanceOf[ListEntry]
-        }
-
-        val app: ProxiedApp = apps(position)
-
-        entry.text.setText(app.name)
-        entry.icon.setImageDrawable(app.icon)
-        val switch = entry.switch
-        switch.setTag(app)
-        switch.setChecked(proxiedApps.contains(app.packageName))
-        entry.text.setTag(switch)
-        convertView
-      }
-    }
-  }
+  private val appsLoading = new AtomicBoolean
 
   private def setProxied(pn: String, proxied: Boolean) = if (proxied) proxiedApps.add(pn) else proxiedApps.remove(pn)
 
@@ -145,6 +129,7 @@ class AppManager extends AppCompatActivity with OnCheckedChangeListener with OnC
   }
 
   override def onDestroy() {
+    instance = null
     super.onDestroy()
     if (handler != null) {
       handler.removeCallbacksAndMessages(null)
@@ -186,7 +171,7 @@ class AppManager extends AppCompatActivity with OnCheckedChangeListener with OnC
                 // Restart activity
                 appListView.setVisibility(View.GONE)
                 loadingView.setVisibility(View.VISIBLE)
-                if (appsLoading) appsLoading = false else loadAppsAsync()
+                reloadApps()
                 return true
               }
             }
@@ -252,13 +237,49 @@ class AppManager extends AppCompatActivity with OnCheckedChangeListener with OnC
         }
       }
     })
+    instance = this
     loadAppsAsync()
   }
 
+  def reloadApps() = if (!appsLoading.compareAndSet(true, false)) loadAppsAsync()
   def loadAppsAsync() {
+    if (!appsLoading.compareAndSet(false, true)) return
     ThrowableFuture {
-      while (!appsLoading) loadApps()
-      appsLoading = false
+      do {
+        proxiedApps = ShadowsocksApplication.settings.getString(Key.proxied, "").split('\n').to[mutable.HashSet]
+        appsLoading.set(true)
+        apps = getApps(getPackageManager).sortWith((a, b) => {
+          val aProxied = proxiedApps.contains(a.packageName)
+          if (aProxied ^ proxiedApps.contains(b.packageName)) aProxied else a.name.compareToIgnoreCase(b.name) < 0
+        })
+        adapter = new ArrayAdapter[ProxiedApp](this, R.layout.layout_apps_item, R.id.itemtext, apps) {
+          override def getView(position: Int, view: View, parent: ViewGroup): View = {
+            var convertView = view
+            var entry: ListEntry = null
+            if (convertView == null) {
+              convertView = getLayoutInflater.inflate(R.layout.layout_apps_item, parent, false)
+              entry = new ListEntry(convertView.findViewById(R.id.itemcheck).asInstanceOf[Switch],
+                convertView.findViewById(R.id.itemtext).asInstanceOf[TextView],
+                convertView.findViewById(R.id.itemicon).asInstanceOf[ImageView])
+              convertView.setOnClickListener(AppManager.this)
+              convertView.setTag(entry)
+              entry.switch.setOnCheckedChangeListener(AppManager.this)
+            } else {
+              entry = convertView.getTag.asInstanceOf[ListEntry]
+            }
+
+            val app: ProxiedApp = apps(position)
+
+            entry.text.setText(app.name)
+            entry.icon.setImageDrawable(app.icon)
+            val switch = entry.switch
+            switch.setTag(app)
+            switch.setChecked(proxiedApps.contains(app.packageName))
+            entry.text.setTag(switch)
+            convertView
+          }
+        }
+      } while (!appsLoading.compareAndSet(true, false))
       handler.post(() => {
         appListView.setAdapter(adapter)
         Utils.crossFade(AppManager.this, loadingView, appListView)
@@ -267,7 +288,7 @@ class AppManager extends AppCompatActivity with OnCheckedChangeListener with OnC
   }
 
   def saveAppSettings(context: Context) {
-    if (!appsLoading) ShadowsocksApplication.settings.edit.putString(Key.proxied, proxiedApps.mkString("\n")).apply
+    if (!appsLoading.get) ShadowsocksApplication.settings.edit.putString(Key.proxied, proxiedApps.mkString("\n")).apply
   }
 
   var handler: Handler = null
diff --git a/src/main/scala/com/github/shadowsocks/AppManagerReceiver.scala b/src/main/scala/com/github/shadowsocks/AppManagerReceiver.scala
deleted file mode 100644
index f3170f21..00000000
--- a/src/main/scala/com/github/shadowsocks/AppManagerReceiver.scala
+++ /dev/null
@@ -1,11 +0,0 @@
-package com.github.shadowsocks
-
-import android.content.{Intent, Context, BroadcastReceiver}
-
-/**
-  * @author Mygod
-  */
-class AppManagerReceiver extends BroadcastReceiver {
-  override def onReceive(context: Context, intent: Intent) = if (intent.getAction != Intent.ACTION_PACKAGE_REMOVED ||
-    !intent.getBooleanExtra(Intent.EXTRA_REPLACING, false)) AppManager.synchronized(AppManager.cachedApps = null)
-}
diff --git a/src/main/scala/com/github/shadowsocks/BaseService.scala b/src/main/scala/com/github/shadowsocks/BaseService.scala
index 0c81975a..67ea792d 100644
--- a/src/main/scala/com/github/shadowsocks/BaseService.scala
+++ b/src/main/scala/com/github/shadowsocks/BaseService.scala
@@ -42,7 +42,7 @@ package com.github.shadowsocks
 import java.util.{Timer, TimerTask}
 
 import android.app.Service
-import android.content.Context
+import android.content.{Intent, Context}
 import android.os.{Handler, RemoteCallbackList}
 import com.github.shadowsocks.aidl.{Config, IShadowsocksService, IShadowsocksServiceCallback}
 import com.github.shadowsocks.utils.{State, TrafficMonitor, TrafficMonitorThread}
@@ -50,7 +50,6 @@ import com.github.shadowsocks.utils.{State, TrafficMonitor, TrafficMonitorThread
 trait BaseService extends Service {
 
   @volatile private var state = State.STOPPED
-  @volatile private var callbackCount = 0
   @volatile protected var config: Config = null
 
   var timer: Timer = null
@@ -70,32 +69,28 @@ trait BaseService extends Service {
     override def unregisterCallback(cb: IShadowsocksServiceCallback) {
       if (cb != null ) {
         callbacks.unregister(cb)
-        callbackCount -= 1
       }
-      if (callbackCount == 0 && timer != null) {
+      if (callbacks.getRegisteredCallbackCount == 0 && timer != null) {
         timer.cancel()
         timer = null
       }
-      if (callbackCount == 0 && state == State.STOPPED) {
-        stopBackgroundService()
-      }
     }
 
     override def registerCallback(cb: IShadowsocksServiceCallback) {
       if (cb != null) {
-        if (callbackCount == 0 && timer == null) {
+        callbacks.register(cb)
+        if (callbacks.getRegisteredCallbackCount != 0 && timer == null) {
           val task = new TimerTask {
             def run {
-              TrafficMonitor.updateRate()
-              updateTrafficRate(TrafficMonitor.getTxRate, TrafficMonitor.getRxRate,
-                TrafficMonitor.getTxTotal, TrafficMonitor.getRxTotal)
+              if (TrafficMonitor.updateRate()) updateTrafficRate()
             }
           }
           timer = new Timer(true)
           timer.schedule(task, 1000, 1000)
         }
-        callbacks.register(cb)
-        callbackCount += 1
+        TrafficMonitor.updateRate()
+        cb.trafficUpdated(TrafficMonitor.getTxRate, TrafficMonitor.getRxRate,
+          TrafficMonitor.getTxTotal, TrafficMonitor.getRxTotal)
       }
     }
 
@@ -115,6 +110,7 @@ trait BaseService extends Service {
   def startRunner(config: Config) {
     this.config = config
 
+    startService(new Intent(getContext, getClass))
     TrafficMonitor.reset()
     trafficMonitorThread = new TrafficMonitorThread()
     trafficMonitorThread.start()
@@ -122,39 +118,38 @@ trait BaseService extends Service {
 
   def stopRunner() {
     // Make sure update total traffic when stopping the runner
-    updateTrafficTotal(TrafficMonitor.getDeltaTx, TrafficMonitor.getDeltaRx)
+    updateTrafficTotal(TrafficMonitor.txTotal, TrafficMonitor.rxTotal)
 
     TrafficMonitor.reset()
     if (trafficMonitorThread != null) {
       trafficMonitorThread.stopThread()
       trafficMonitorThread = null
     }
+
+    // change the state
+    changeState(State.STOPPED)
+
+    // stop the service if nothing has bound to it
+    stopSelf()
   }
 
   def updateTrafficTotal(tx: Long, rx: Long) {
-    val handler = new Handler(getContext.getMainLooper)
-    handler.post(() => {
-      val config = this.config  // avoid race conditions without locking
-      if (config != null) {
-        ShadowsocksApplication.profileManager.getProfile(config.profileId) match {
-          case Some(profile) =>
-            profile.tx += tx
-            profile.rx += rx
-            ShadowsocksApplication.profileManager.updateProfile(profile)
-          case None => // Ignore
-        }
+    val config = this.config  // avoid race conditions without locking
+    if (config != null) {
+      ShadowsocksApplication.profileManager.getProfile(config.profileId) match {
+        case Some(profile) =>
+          profile.tx += tx
+          profile.rx += rx
+          ShadowsocksApplication.profileManager.updateProfile(profile)
+        case None => // Ignore
       }
-    })
+    }
   }
 
-  def stopBackgroundService()
   def getServiceMode: Int
   def getTag: String
   def getContext: Context
 
-  def getCallbackCount: Int = {
-    callbackCount
-  }
   def getState: Int = {
     state
   }
@@ -162,10 +157,14 @@ trait BaseService extends Service {
     changeState(s, null)
   }
 
-  def updateTrafficRate(txRate: String, rxRate: String, txTotal: String, rxTotal: String) {
+  def updateTrafficRate() {
     val handler = new Handler(getContext.getMainLooper)
     handler.post(() => {
-      if (callbackCount > 0) {
+      if (callbacks.getRegisteredCallbackCount > 0) {
+        val txRate = TrafficMonitor.getTxRate
+        val rxRate = TrafficMonitor.getRxRate
+        val txTotal = TrafficMonitor.getTxTotal
+        val rxTotal = TrafficMonitor.getRxTotal
         val n = callbacks.beginBroadcast()
         for (i <- 0 until n) {
           try {
@@ -182,7 +181,7 @@ trait BaseService extends Service {
   protected def changeState(s: Int, msg: String) {
     val handler = new Handler(getContext.getMainLooper)
     handler.post(() => if (state != s) {
-      if (callbackCount > 0) {
+      if (callbacks.getRegisteredCallbackCount > 0) {
         val n = callbacks.beginBroadcast()
         for (i <- 0 until n) {
           try {
diff --git a/src/main/scala/com/github/shadowsocks/ProfileManagerActivity.scala b/src/main/scala/com/github/shadowsocks/ProfileManagerActivity.scala
index 3eef2882..401cbd6d 100644
--- a/src/main/scala/com/github/shadowsocks/ProfileManagerActivity.scala
+++ b/src/main/scala/com/github/shadowsocks/ProfileManagerActivity.scala
@@ -218,6 +218,15 @@ class ProfileManagerActivity extends AppCompatActivity with OnMenuItemClickListe
     }
   }
 
+  override def onStart() {
+    super.onStart()
+    registerCallback
+  }
+  override def onStop() {
+    super.onStop()
+    unregisterCallback
+  }
+
   override def onDestroy {
     deattachService()
     super.onDestroy
diff --git a/src/main/scala/com/github/shadowsocks/ServiceBoundContext.scala b/src/main/scala/com/github/shadowsocks/ServiceBoundContext.scala
index c304f559..f50cd606 100644
--- a/src/main/scala/com/github/shadowsocks/ServiceBoundContext.scala
+++ b/src/main/scala/com/github/shadowsocks/ServiceBoundContext.scala
@@ -13,20 +13,12 @@ trait ServiceBoundContext extends Context {
   class ShadowsocksServiceConnection extends ServiceConnection {
     override def onServiceConnected(name: ComponentName, service: IBinder) {
       bgService = IShadowsocksService.Stub.asInterface(service)
-      if (callback != null) try {
-        bgService.registerCallback(callback)
-      } catch {
-        case ignored: RemoteException => // Nothing
-      }
+      registerCallback
       ServiceBoundContext.this.onServiceConnected()
     }
     override def onServiceDisconnected(name: ComponentName) {
       if (callback != null) {
-        try {
-          if (bgService != null) bgService.unregisterCallback(callback)
-        } catch {
-          case ignored: RemoteException => // Nothing
-        }
+        unregisterCallback
         callback = null
       }
       ServiceBoundContext.this.onServiceDisconnected()
@@ -34,11 +26,25 @@ trait ServiceBoundContext extends Context {
     }
   }
 
+  def registerCallback = if (bgService != null && callback != null && !callbackRegistered) try {
+    bgService.registerCallback(callback)
+    callbackRegistered = true
+  } catch {
+    case ignored: RemoteException => // Nothing
+  }
+  def unregisterCallback = if (bgService != null && callback != null && callbackRegistered) try {
+    bgService.unregisterCallback(callback)
+    callbackRegistered = false
+  } catch {
+    case ignored: RemoteException => // Nothing
+  }
+
   def onServiceConnected() = ()
   def onServiceDisconnected() = ()
 
   private var callback: IShadowsocksServiceCallback.Stub = _
   private var connection: ShadowsocksServiceConnection = _
+  private var callbackRegistered: Boolean = _
 
   // Variables
   var bgService: IShadowsocksService = _
@@ -54,19 +60,13 @@ trait ServiceBoundContext extends Context {
 
       connection = new ShadowsocksServiceConnection()
       bindService(intent, connection, Context.BIND_AUTO_CREATE)
-
-      startService(new Intent(this, s))
     }
   }
 
   def deattachService() {
     if (bgService != null) {
       if (callback != null) {
-        try {
-          bgService.unregisterCallback(callback)
-        } catch {
-          case ignored: RemoteException => // Nothing
-        }
+        unregisterCallback
         callback = null
       }
       if (connection != null) {
diff --git a/src/main/scala/com/github/shadowsocks/Shadowsocks.scala b/src/main/scala/com/github/shadowsocks/Shadowsocks.scala
index 2c739d72..2f949e41 100644
--- a/src/main/scala/com/github/shadowsocks/Shadowsocks.scala
+++ b/src/main/scala/com/github/shadowsocks/Shadowsocks.scala
@@ -461,8 +461,13 @@ class Shadowsocks
     preferences.update(profile)
   }
 
+  override def onStart() {
+    super.onStart()
+    registerCallback
+  }
   override def onStop() {
     super.onStop()
+    unregisterCallback
     clearDialog()
   }
 
diff --git a/src/main/scala/com/github/shadowsocks/ShadowsocksNatService.scala b/src/main/scala/com/github/shadowsocks/ShadowsocksNatService.scala
index f25becb5..45f93c87 100644
--- a/src/main/scala/com/github/shadowsocks/ShadowsocksNatService.scala
+++ b/src/main/scala/com/github/shadowsocks/ShadowsocksNatService.scala
@@ -458,8 +458,6 @@ class ShadowsocksNatService extends BaseService {
 
   override def stopRunner() {
 
-    super.stopRunner()
-
     // channge the state
     changeState(State.STOPPING)
 
@@ -476,17 +474,7 @@ class ShadowsocksNatService extends BaseService {
     // reset NAT
     killProcesses()
 
-    // stop the service if no callback registered
-    if (getCallbackCount == 0) {
-      stopSelf()
-    }
-
-    // change the state
-    changeState(State.STOPPED)
-  }
-
-  override def stopBackgroundService() {
-    stopSelf()
+    super.stopRunner()
   }
 
   override def getTag = TAG
diff --git a/src/main/scala/com/github/shadowsocks/ShadowsocksNotification.scala b/src/main/scala/com/github/shadowsocks/ShadowsocksNotification.scala
index f8f8b06e..4c609f53 100644
--- a/src/main/scala/com/github/shadowsocks/ShadowsocksNotification.scala
+++ b/src/main/scala/com/github/shadowsocks/ShadowsocksNotification.scala
@@ -2,7 +2,7 @@ package com.github.shadowsocks
 
 import java.util.Locale
 
-import android.app.{KeyguardManager, PendingIntent}
+import android.app.{KeyguardManager, NotificationManager, PendingIntent}
 import android.content.{BroadcastReceiver, Context, Intent, IntentFilter}
 import android.os.PowerManager
 import android.support.v4.app.NotificationCompat
@@ -16,6 +16,7 @@ import com.github.shadowsocks.utils.{Action, State, Utils}
   */
 class ShadowsocksNotification(private val service: BaseService, profileName: String, visible: Boolean = false) {
   private lazy val keyGuard = service.getSystemService(Context.KEYGUARD_SERVICE).asInstanceOf[KeyguardManager]
+  private lazy val nm = service.getSystemService(Context.NOTIFICATION_SERVICE).asInstanceOf[NotificationManager]
   private lazy val callback = new Stub {
     override def stateChanged(state: Int, msg: String) = () // ignore
     override def trafficUpdated(txRate: String, rxRate: String, txTotal: String, rxTotal: String) {
@@ -27,6 +28,7 @@ class ShadowsocksNotification(private val service: BaseService, profileName: Str
   }
   private var lockReceiver: BroadcastReceiver = _
   private var callbackRegistered: Boolean = _
+  private var started: Boolean = _
 
   private val builder = new NotificationCompat.Builder(service)
     .setWhen(0)
@@ -73,8 +75,10 @@ class ShadowsocksNotification(private val service: BaseService, profileName: Str
     show()
   } else if (forceShow) show()
 
-  def notification = builder.build()
-  def show() = service.startForeground(1, notification)
+  def show() = if (started) nm.notify(1, builder.build) else {
+    service.startForeground(1, builder.build)
+    started = true
+  }
 
   def destroy() {
     if (lockReceiver != null) {
diff --git a/src/main/scala/com/github/shadowsocks/ShadowsocksVpnService.scala b/src/main/scala/com/github/shadowsocks/ShadowsocksVpnService.scala
index 849af214..d0ecfeaf 100644
--- a/src/main/scala/com/github/shadowsocks/ShadowsocksVpnService.scala
+++ b/src/main/scala/com/github/shadowsocks/ShadowsocksVpnService.scala
@@ -113,8 +113,6 @@ class ShadowsocksVpnService extends VpnService with BaseService {
 
   override def stopRunner() {
 
-    super.stopRunner()
-
     if (vpnThread != null) {
       vpnThread.stopThread()
       vpnThread = null
@@ -136,19 +134,13 @@ class ShadowsocksVpnService extends VpnService with BaseService {
       conn = null
     }
 
-    // stop the service if no callback registered
-    if (getCallbackCount == 0) {
-      stopSelf()
-    }
-
     // clean up recevier
     if (closeReceiver != null) {
       unregisterReceiver(closeReceiver)
       closeReceiver = null
     }
 
-    // channge the state
-    changeState(State.STOPPED)
+    super.stopRunner()
   }
 
   def getVersionName: String = {
@@ -458,10 +450,6 @@ class ShadowsocksVpnService extends VpnService with BaseService {
     fd
   }
 
-  override def stopBackgroundService() {
-    stopSelf()
-  }
-
   override def getTag = TAG
 
   override def getServiceMode = Mode.VPN
diff --git a/src/main/scala/com/github/shadowsocks/ShadowsocksVpnThread.scala b/src/main/scala/com/github/shadowsocks/ShadowsocksVpnThread.scala
index 6946f8cd..f3fbb3e2 100644
--- a/src/main/scala/com/github/shadowsocks/ShadowsocksVpnThread.scala
+++ b/src/main/scala/com/github/shadowsocks/ShadowsocksVpnThread.scala
@@ -45,7 +45,12 @@ import java.util.concurrent.Executors
 import android.net.{LocalServerSocket, LocalSocket, LocalSocketAddress}
 import android.util.Log
 
+object ShadowsocksVpnThread {
+  val getInt = classOf[FileDescriptor].getDeclaredMethod("getInt$")
+}
+
 class ShadowsocksVpnThread(vpnService: ShadowsocksVpnService) extends Thread {
+  import ShadowsocksVpnThread._
 
   val TAG = "ShadowsocksVpnService"
   val PATH = "/data/data/com.github.shadowsocks/protect_path"
@@ -103,11 +108,8 @@ class ShadowsocksVpnThread(vpnService: ShadowsocksVpnService) extends Thread {
             val fds = socket.getAncillaryFileDescriptors
 
             if (fds.nonEmpty) {
-              var ret = false
-
-              val getInt = classOf[FileDescriptor].getDeclaredMethod("getInt$")
               val fd = getInt.invoke(fds(0)).asInstanceOf[Int]
-              ret = vpnService.protect(fd)
+              val ret = vpnService.protect(fd)
 
               // Trick to close file decriptor
               System.jniclose(fd)
diff --git a/src/main/scala/com/github/shadowsocks/utils/TrafficMonitor.scala b/src/main/scala/com/github/shadowsocks/utils/TrafficMonitor.scala
index d34b526f..168fd6ed 100644
--- a/src/main/scala/com/github/shadowsocks/utils/TrafficMonitor.scala
+++ b/src/main/scala/com/github/shadowsocks/utils/TrafficMonitor.scala
@@ -5,26 +5,20 @@ import java.text.DecimalFormat
 
 import com.github.shadowsocks.{R, ShadowsocksApplication}
 
-case class Traffic(tx: Long, rx: Long, timestamp: Long)
-
 object TrafficMonitor {
-  var last: Traffic = getTraffic(0, 0)
-
   // Bytes per second
-  var txRate: Long = 0
-  var rxRate: Long = 0
+  var txRate: Long = _
+  var rxRate: Long = _
 
   // Bytes for the current session
-  var txTotal: Long = 0
-  var rxTotal: Long = 0
+  var txTotal: Long = _
+  var rxTotal: Long = _
 
   // Bytes for the last query
-  var txLast: Long = 0
-  var rxLast: Long = 0
-
-  def getTraffic(tx: Long, rx: Long): Traffic = {
-    new Traffic(tx, rx, System.currentTimeMillis())
-  }
+  var txLast: Long = _
+  var rxLast: Long = _
+  var timestampLast: Long = _
+  @volatile var dirty = true
 
   private val units = Array("KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB", "BB", "NB", "DB", "CB")
   private val numberFormat = new DecimalFormat("@@@")
@@ -39,21 +33,42 @@ object TrafficMonitor {
     else numberFormat.format(n) + ' ' + units(i)
   }
 
-  def updateRate() {
-    val now = getTraffic(txTotal, rxTotal)
-    val delta = now.timestamp - last.timestamp
-    val deltaTx = now.tx - last.tx
-    val deltaRx = now.rx - last.rx
+  def updateRate() = {
+    val now = System.currentTimeMillis()
+    val delta = now - timestampLast
+    var updated = false
     if (delta != 0) {
-      txRate = deltaTx * 1000 / delta
-      rxRate = deltaRx * 1000 / delta
+      if (dirty) {
+        txRate = (txTotal - txLast) * 1000 / delta
+        rxRate = (rxTotal - rxLast) * 1000 / delta
+        txLast = txTotal
+        rxLast = rxTotal
+        dirty = false
+        updated = true
+      } else {
+        if (txRate != 0) {
+          txRate = 0
+          updated = true
+        }
+        if (rxRate != 0) {
+          rxRate = 0
+          updated = true
+        }
+      }
+      timestampLast = now
     }
-    last = now
+    updated
   }
 
   def update(tx: Long, rx: Long) {
-    txTotal = tx
-    rxTotal = rx
+    if (txTotal != tx) {
+      txTotal = tx
+      dirty = true
+    }
+    if (rxTotal != rx) {
+      rxTotal = rx
+      dirty = true
+    }
   }
 
   def reset() {
@@ -63,7 +78,7 @@ object TrafficMonitor {
     rxTotal = 0
     txLast = 0
     rxLast = 0
-    last = getTraffic(0, 0)
+    dirty = true
   }
 
   def getTxTotal(): String = {
@@ -89,17 +104,5 @@ object TrafficMonitor {
   def getRate(): String = {
     formatTraffic(txRate + rxRate)
   }
-
-  def getDeltaTx(): Long = {
-    val last = txLast
-    txLast = txTotal
-    txTotal - last
-  }
-
-  def getDeltaRx(): Long = {
-    val last = rxLast
-    rxLast = rxTotal
-    rxTotal - last
-  }
 }
 
diff --git a/src/main/scala/com/github/shadowsocks/utils/TrafficMonitorThread.scala b/src/main/scala/com/github/shadowsocks/utils/TrafficMonitorThread.scala
index 15e9a43c..ec4b890e 100644
--- a/src/main/scala/com/github/shadowsocks/utils/TrafficMonitorThread.scala
+++ b/src/main/scala/com/github/shadowsocks/utils/TrafficMonitorThread.scala
@@ -40,11 +40,11 @@
 package com.github.shadowsocks.utils
 
 import java.io.{File, IOException}
+import java.nio.{ByteBuffer, ByteOrder}
 import java.util.concurrent.Executors
 
 import android.net.{LocalServerSocket, LocalSocket, LocalSocketAddress}
 import android.util.Log
-import com.github.shadowsocks.BaseService
 
 class TrafficMonitorThread() extends Thread {
 
@@ -99,16 +99,10 @@ class TrafficMonitorThread() extends Thread {
             val input = socket.getInputStream
             val output = socket.getOutputStream
 
-            val buffer = new Array[Byte](256)
-            val size = input.read(buffer)
-
-            val array = new Array[Byte](size)
-            Array.copy(buffer, 0, array, 0, size)
-
-            val stat = new String(array, "UTF-8").split("\\|")
-            if (stat.length == 2) {
-              TrafficMonitor.update(stat(0).toLong, stat(1).toLong)
-            }
+            val buffer = new Array[Byte](16)
+            if (input.read(buffer) != 16) throw new IOException("Unexpected traffic stat length")
+            val stat = ByteBuffer.wrap(buffer).order(ByteOrder.LITTLE_ENDIAN)
+            TrafficMonitor.update(stat.getLong(0), stat.getLong(8))
 
             output.write(0)