Synchronization bug fix in broadcast implementations

core/src/main/scala/spark/broadcast/BitTorrentBroadcast.scala

@@ -307,9 +307,11 @@ extends Broadcast[T] with Logging with Serializable {
       var threadPool = Utils.newDaemonFixedThreadPool(MultiTracker.MaxChatSlots)
 
       while (hasBlocks.get < totalBlocks) {
-        var numThreadsToCreate =
-          math.min(listOfSources.size, MultiTracker.MaxChatSlots) -
+        var numThreadsToCreate = 0
+        listOfSources.synchronized {
+          numThreadsToCreate = math.min(listOfSources.size, MultiTracker.MaxChatSlots) -
           threadPool.getActiveCount
+        }
 
         while (hasBlocks.get < totalBlocks && numThreadsToCreate > 0) {
           var peerToTalkTo = pickPeerToTalkToRandom
@@ -732,10 +734,14 @@ extends Broadcast[T] with Logging with Serializable {
               // Stop broadcast if at least one worker has connected and
               // everyone connected so far are done. Comparing with
               // listOfSources.size - 1, because it includes the Guide itself
-              if (listOfSources.size > 1 &&
-                setOfCompletedSources.size == listOfSources.size - 1) {
-                stopBroadcast = true
-                logInfo("GuideMultipleRequests Timeout. stopBroadcast == true.")
+              listOfSources.synchronized {
+                setOfCompletedSources.synchronized {
+                  if (listOfSources.size > 1 &&
+                    setOfCompletedSources.size == listOfSources.size - 1) {
+                    stopBroadcast = true
+                    logInfo("GuideMultipleRequests Timeout. stopBroadcast == true.")
+                  }
+                }
               }
             }
           }

core/src/main/scala/spark/broadcast/TreeBroadcast.scala

@@ -290,15 +290,17 @@ extends Broadcast[T] with Logging with Serializable {
             clientSocket = serverSocket.accept
           } catch {
             case e: Exception => {
-              logError("GuideMultipleRequests Timeout.")
-
               // Stop broadcast if at least one worker has connected and
-              // everyone connected so far are done. 
-              // Comparing with listOfSources.size - 1, because the Guide itself 
-              // is included
-              if (listOfSources.size > 1 &&
-                setOfCompletedSources.size == listOfSources.size - 1) {
-                stopBroadcast = true
+              // everyone connected so far are done. Comparing with
+              // listOfSources.size - 1, because it includes the Guide itself
+              listOfSources.synchronized {
+                setOfCompletedSources.synchronized {
+                  if (listOfSources.size > 1 &&
+                    setOfCompletedSources.size == listOfSources.size - 1) {
+                    stopBroadcast = true
+                    logInfo("GuideMultipleRequests Timeout. stopBroadcast == true.")
+                  }
+                }
               }
             }
           }
@@ -490,7 +492,7 @@ extends Broadcast[T] with Logging with Serializable {
             serverSocket.setSoTimeout(MultiTracker.ServerSocketTimeout)
             clientSocket = serverSocket.accept
           } catch {
-            case e: Exception => logError("ServeMultipleRequests Timeout.")
+            case e: Exception => { }
           }
           
           if (clientSocket != null) {