Use Netty HashedWheelTimer

core/src/main/scala/org/apache/spark/network/nio/ConnectionManager.scala

@@ -24,14 +24,14 @@ import java.nio.channels._
 import java.nio.channels.spi._
 import java.util.concurrent.atomic.AtomicInteger
 import java.util.concurrent.{LinkedBlockingDeque, ThreadPoolExecutor, TimeUnit}
-import java.util.{Timer, TimerTask}
 
 import scala.collection.mutable.{ArrayBuffer, HashMap, HashSet, SynchronizedMap, SynchronizedQueue}
 import scala.concurrent.duration._
 import scala.concurrent.{Await, ExecutionContext, Future, Promise}
 import scala.language.postfixOps
 
 import com.google.common.base.Charsets.UTF_8
+import io.netty.util.{Timeout, TimerTask, HashedWheelTimer}
 
 import org.apache.spark._
 import org.apache.spark.network.sasl.{SparkSaslClient, SparkSaslServer}
@@ -77,7 +77,8 @@ private[nio] class ConnectionManager(
   }
 
   private val selector = SelectorProvider.provider.openSelector()
-  private val ackTimeoutMonitor = new Timer("AckTimeoutMonitor", true)
+  private val ackTimeoutMonitor =
+    new HashedWheelTimer(Utils.namedThreadFactory("AckTimeoutMonitor"))
 
   private val ackTimeout = conf.getInt("spark.core.connection.ack.wait.timeout", 60)
 
@@ -903,8 +904,8 @@ private[nio] class ConnectionManager(
     // memory leaks since cancelled TimerTasks won't necessarily be garbage collected until they are
     // scheduled to run.  Therefore, extract the message id from outside of the task:
     val messageId = message.id
-    val timeoutTask = new TimerTask {
-      override def run(): Unit = {
+    val timeoutTask: TimerTask = new TimerTask {
+      override def run(timeout: Timeout): Unit = {
         messageStatuses.synchronized {
           messageStatuses.remove(messageId).foreach ( s => {
             val e = new IOException("sendMessageReliably failed because ack " +
@@ -917,8 +918,10 @@ private[nio] class ConnectionManager(
       }
     }
 
+    val timoutTaskHandle = ackTimeoutMonitor.newTimeout(timeoutTask, ackTimeout, TimeUnit.SECONDS)
+
     val status = new MessageStatus(message, connectionManagerId, s => {
-      timeoutTask.cancel()
+      timoutTaskHandle.cancel()
       s match {
         case scala.util.Failure(e) =>
           // Indicates a failure where we either never sent or never got ACK'd
@@ -947,7 +950,6 @@ private[nio] class ConnectionManager(
       messageStatuses += ((message.id, status))
     }
 
-    ackTimeoutMonitor.schedule(timeoutTask, ackTimeout * 1000)
     sendMessage(connectionManagerId, message)
     promise.future
   }
@@ -957,7 +959,7 @@ private[nio] class ConnectionManager(
   }
 
   def stop() {
-    ackTimeoutMonitor.cancel()
+    ackTimeoutMonitor.stop()
     selectorThread.interrupt()
     selectorThread.join()
     selector.close()