Modified Patch according to comments

core/src/main/scala/spark/network/Connection.scala

@@ -136,10 +136,10 @@ extends Connection(SocketChannel.open, selector_) {
           if (chunk.isDefined) {
             messages += message  // this is probably incorrect, it wont work as fifo
             if (!message.started) {
-		logDebug("Starting to send [" + message + "]")
- 		message.started = true
-	 	message.startTime = System.currentTimeMillis
-	    }
+              logDebug("Starting to send [" + message + "]")
+              message.started = true
+              message.startTime = System.currentTimeMillis
+            }
             return chunk 
           } else {
             /*logInfo("Finished sending [" + message + "] to [" + remoteConnectionManagerId + "]")*/

core/src/main/scala/spark/network/ConnectionManager.scala

@@ -43,12 +43,12 @@ private[spark] class ConnectionManager(port: Int) extends Logging {
   }
   
   val selector = SelectorProvider.provider.openSelector()
-  val handleMessageExecutor = Executors.newFixedThreadPool(20) 
+  val handleMessageExecutor = Executors.newFixedThreadPool(System.getProperty("spark.core.connection.handler.threads","20").toInt)
   val serverChannel = ServerSocketChannel.open()
   val connectionsByKey = new HashMap[SelectionKey, Connection] with SynchronizedMap[SelectionKey, Connection] 
   val connectionsById = new HashMap[ConnectionManagerId, SendingConnection] with SynchronizedMap[ConnectionManagerId, SendingConnection]
   val messageStatuses = new HashMap[Int, MessageStatus] 
-  val connectionRequests = new HashMap[ConnectionManagerId, SendingConnection] with SynchronizedMap[ConnectionManagerId, SendingConnection] 
+  val connectionRequests = new HashMap[ConnectionManagerId, SendingConnection] with SynchronizedMap[ConnectionManagerId, SendingConnection]
   val keyInterestChangeRequests = new SynchronizedQueue[(SelectionKey, Int)]
   val sendMessageRequests = new Queue[(Message, SendingConnection)]
 
@@ -78,9 +78,8 @@ private[spark] class ConnectionManager(port: Int) extends Logging {
 
   def run() {
     try {
-      while(!selectorThread.isInterrupted) {   
+      while(!selectorThread.isInterrupted) {
         for( (connectionManagerId, sendingConnection) <- connectionRequests) {
-          //val sendingConnection = connectionRequests.dequeue
           sendingConnection.connect() 
           addConnection(sendingConnection)
           connectionRequests -= connectionManagerId
@@ -465,7 +464,7 @@ private[spark] object ConnectionManager {
           val bufferMessage = Message.createBufferMessage(buffer.duplicate)
           manager.sendMessageReliably(manager.id, bufferMessage)
         }).foreach(f => {
-          val g = Await.result(f, 10 second)
+          val g = Await.result(f, 1 second)
           if (!g.isDefined) println("Failed")
         })
       val finishTime = System.currentTimeMillis

core/src/main/scala/spark/network/ConnectionManagerTest.scala

@@ -13,8 +13,14 @@ import akka.util.duration._
 
 private[spark] object ConnectionManagerTest extends Logging{
   def main(args: Array[String]) {
-    if (args.length < 5) {
-      println("Usage: ConnectionManagerTest <mesos cluster> <slaves file> <num of tasks> <size of msg> <count>")
+    //<mesos cluster> - the master URL
+    //<slaves file> - a list slaves to run connectionTest on
+    //[num of tasks] - the number of parallel tasks to be initiated default is number of slave hosts
+    //[size of msg in MB (integer)] - the size of messages to be sent in each task, default is 10
+    //[count] - how many times to run, default is 3
+    //[await time in seconds] : await time (in seconds), default is 600
+    if (args.length < 2) {
+      println("Usage: ConnectionManagerTest <mesos cluster> <slaves file> [num of tasks] [size of msg in MB (integer)] [count] [await time in seconds)] ")
       System.exit(1)
     }
     
@@ -29,14 +35,17 @@ private[spark] object ConnectionManagerTest extends Logging{
 
     /*println("Slaves")*/
     /*slaves.foreach(println)*/
-    val tasknum = args(2).toInt
+    val tasknum = if (args.length > 2) args(2).toInt else slaves.length
+    val size = ( if (args.length > 3) (args(3).toInt) else 10 ) * 1024 * 1024 
+    val count = if (args.length > 4) args(4).toInt else 3
+    val awaitTime = (if (args.length > 5) args(5).toInt else 600 ).second
+    println("Running "+count+" rounds of test: " + "parallel tasks = " + tasknum + ", msg size = " + size/1024/1024 + " MB, awaitTime = " + awaitTime)
     val slaveConnManagerIds = sc.parallelize(0 until tasknum, tasknum).map(
         i => SparkEnv.get.connectionManager.id).collect()
     println("\nSlave ConnectionManagerIds")
     slaveConnManagerIds.foreach(println)
     println
 
-    val count = args(4).toInt
     (0 until count).foreach(i => {
       val resultStrs = sc.parallelize(0 until tasknum, tasknum).map(i => {
         val connManager = SparkEnv.get.connectionManager
@@ -46,7 +55,6 @@ private[spark] object ConnectionManagerTest extends Logging{
           None
         })
 
-        val size = (args(3).toInt) * 1024  * 1024 
         val buffer = ByteBuffer.allocate(size).put(Array.tabulate[Byte](size)(x => x.toByte))
         buffer.flip
         
@@ -56,7 +64,7 @@ private[spark] object ConnectionManagerTest extends Logging{
           logInfo("Sending [" + bufferMessage + "] to [" + slaveConnManagerId + "]")
           connManager.sendMessageReliably(slaveConnManagerId, bufferMessage)
         })
-        val results = futures.map(f => Await.result(f, 999.second))
+        val results = futures.map(f => Await.result(f, awaitTime))
         val finishTime = System.currentTimeMillis
         Thread.sleep(5000)