Various minor changes:

- added forwarders to SO objects to Inet
 - added batch read support for UDP
 - changed write for UDP
 - SimpleSender is now registered as everone else

akka-actor-tests/src/test/scala/akka/io/IntegrationSpec.scala

@@ -6,7 +6,6 @@ package akka.io
 
 import akka.testkit.AkkaSpec
 import akka.util.ByteString
-import akka.io.Inet
 import Tcp._
 import TestUtils._
 import akka.testkit.EventFilter
@@ -65,8 +64,8 @@ class IntegrationSpec extends AkkaSpec("akka.loglevel = INFO") with IntegrationS
 
       expectReceivedData(clientHandler, 100000)
 
-      override def bindOptions = List(Inet.SO.SendBufferSize(1024))
-      override def connectOptions = List(Inet.SO.ReceiveBufferSize(1024))
+      override def bindOptions = List(SO.SendBufferSize(1024))
+      override def connectOptions = List(SO.ReceiveBufferSize(1024))
     }
   }
 

akka-actor-tests/src/test/scala/akka/io/UdpConnIntegrationSpec.scala

@@ -19,9 +19,9 @@ class UdpConnIntegrationSpec extends AkkaSpec("akka.loglevel = INFO") with Impli
     (address, commander.sender)
   }
 
-  def connectUdp(localAddress: Option[InetSocketAddress], remoteAddress: InetSocketAddress): ActorRef = {
+  def connectUdp(localAddress: Option[InetSocketAddress], remoteAddress: InetSocketAddress, handler: ActorRef): ActorRef = {
     val commander = TestProbe()
-    commander.send(IO(UdpConn), UdpConn.Connect(testActor, localAddress, remoteAddress, Nil))
+    commander.send(IO(UdpConn), UdpConn.Connect(handler, localAddress, remoteAddress, Nil))
     commander.expectMsg(UdpConn.Connected)
     commander.sender
   }
@@ -32,7 +32,7 @@ class UdpConnIntegrationSpec extends AkkaSpec("akka.loglevel = INFO") with Impli
       val (serverAddress, server) = bindUdp(testActor)
       val data1 = ByteString("To infinity and beyond!")
       val data2 = ByteString("All your datagram belong to us")
-      connectUdp(localAddress = None, serverAddress) ! UdpConn.Send(data1)
+      connectUdp(localAddress = None, serverAddress, testActor) ! UdpConn.Send(data1)
 
       val clientAddress = expectMsgPF() {
         case UdpFF.Received(d, a) ⇒
@@ -55,7 +55,7 @@ class UdpConnIntegrationSpec extends AkkaSpec("akka.loglevel = INFO") with Impli
       val (serverAddress, server) = bindUdp(testActor)
       val data1 = ByteString("To infinity and beyond!")
       val data2 = ByteString("All your datagram belong to us")
-      connectUdp(Some(clientAddress), serverAddress) ! UdpConn.Send(data1)
+      connectUdp(Some(clientAddress), serverAddress, testActor) ! UdpConn.Send(data1)
 
       expectMsgPF() {
         case UdpFF.Received(d, a) ⇒

akka-actor-tests/src/test/scala/akka/io/UdpFFIntegrationSpec.scala

@@ -22,7 +22,7 @@ class UdpFFIntegrationSpec extends AkkaSpec("akka.loglevel = INFO") with Implici
 
   val simpleSender: ActorRef = {
     val commander = TestProbe()
-    commander.send(IO(UdpFF), SimpleSender)
+    commander.send(IO(UdpFF), SimpleSender(Nil))
     commander.expectMsg(SimpleSendReady)
     commander.sender
   }

akka-actor/src/main/resources/reference.conf

@@ -470,6 +470,11 @@ akka {
       # this many times before giving up
       selector-association-retries = 10
 
+      # The maximum number of datagrams that are read in one go,
+      # higher numbers decrease latency, lower numbers increase fairness on
+      # the worker-dispatcher
+      batch-receive-limit = 3
+
       # The number of bytes per direct buffer in the pool used to read or write
       # network data from the kernel.
       direct-buffer-size = 128 KiB
@@ -526,6 +531,11 @@ akka {
       # this many times before giving up
       selector-association-retries = 10
 
+      # The maximum number of datagrams that are read in one go,
+      # higher numbers decrease latency, lower numbers increase fairness on
+      # the worker-dispatcher
+      batch-receive-limit = 3
+
       # The number of bytes per direct buffer in the pool used to read or write
       # network data from the kernel.
       direct-buffer-size = 128 KiB

akka-actor/src/main/scala/akka/io/Inet.scala

@@ -79,4 +79,11 @@ object Inet {
 
   }
 
+  trait SoForwarders {
+    val ReceiveBufferSize = SO.ReceiveBufferSize
+    val ReuseAddress = SO.ReuseAddress
+    val SendBufferSize = SO.SendBufferSize
+    val TrafficClass = SO.TrafficClass
+  }
+
 }

akka-actor/src/main/scala/akka/io/SelectionHandler.scala

@@ -208,6 +208,7 @@ private[io] class SelectionHandler(manager: ActorRef, settings: SelectionHandler
 
   selectorManagementDispatcher.execute(select) // start selection "loop"
 
+  // FIXME: Add possibility to signal failure of task to someone
   abstract class Task extends Runnable {
     def tryRun()
     def run() {

akka-actor/src/main/scala/akka/io/Tcp.scala

@@ -19,7 +19,7 @@ object Tcp extends ExtensionKey[TcpExt] {
   override def get(system: ActorSystem): TcpExt = system.extension(this)
 
   // shared socket options
-  object SO {
+  object SO extends Inet.SoForwarders {
 
     // general socket options
 

akka-actor/src/main/scala/akka/io/Udp.scala

@@ -10,7 +10,7 @@ import akka.actor.{ Props, ActorSystemImpl }
 
 object Udp {
 
-  object SO {
+  object SO extends Inet.SoForwarders {
 
     /**
      * [[akka.io.Inet.SocketOption]] to set the SO_BROADCAST option
@@ -29,9 +29,11 @@ object Udp {
     val NrOfSelectors = getInt("nr-of-selectors")
     val DirectBufferSize = getIntBytes("direct-buffer-size")
     val MaxDirectBufferPoolSize = getInt("max-direct-buffer-pool-size")
+    val BatchReceiveLimit = getInt("batch-receive-limit")
 
     val ManagementDispatcher = getString("management-dispatcher")
 
+    // FIXME: Use new requiring
     require(NrOfSelectors > 0, "nr-of-selectors must be > 0")
 
     override val MaxChannelsPerSelector = if (MaxChannels == -1) -1 else math.max(MaxChannels / NrOfSelectors, 1)

akka-actor/src/main/scala/akka/io/UdpConnection.scala

@@ -13,6 +13,8 @@ import java.nio.channels.DatagramChannel
 import java.nio.channels.SelectionKey._
 import scala.collection.immutable
 import scala.util.control.NonFatal
+import java.nio.ByteBuffer
+import scala.annotation.tailrec
 
 private[io] class UdpConnection(selectorRouter: ActorRef,
                                 handler: ActorRef,
@@ -36,6 +38,7 @@ private[io] class UdpConnection(selectorRouter: ActorRef,
     datagramChannel.configureBlocking(false)
     val socket = datagramChannel.socket
     options.foreach(_.beforeDatagramBind(socket))
+    // FIXME: All bind failures have to be reported to the commander in TCP as well
     localAddress foreach { socket.bind } // will blow up the actor constructor if the bind fails
     datagramChannel.connect(remoteAddress)
     datagramChannel
@@ -46,13 +49,14 @@ private[io] class UdpConnection(selectorRouter: ActorRef,
   def receive = {
     case ChannelRegistered ⇒
       bindCommander ! Connected
+      selector ! ReadInterest
       context.become(connected, discardOld = true)
   }
 
   def connected: Receive = {
     case StopReading     ⇒ selector ! DisableReadInterest
     case ResumeReading   ⇒ selector ! ReadInterest
-    case ChannelReadable ⇒ doRead(handler)
+    case ChannelReadable ⇒ println("read"); doRead(handler)
 
     case Close ⇒
       log.debug("Closing UDP connection to {}", remoteAddress)
@@ -77,14 +81,17 @@ private[io] class UdpConnection(selectorRouter: ActorRef,
   }
 
   def doRead(handler: ActorRef): Unit = {
-    val buffer = bufferPool.acquire()
-    try {
+    @tailrec def innerRead(readsLeft: Int, buffer: ByteBuffer): Unit = {
       buffer.clear()
       buffer.limit(DirectBufferSize)
 
-      if (channel.read(buffer) > 0) handler ! Received(ByteString(buffer))
-
-    } finally {
+      if (channel.read(buffer) > 0) {
+        handler ! Received(ByteString(buffer))
+        innerRead(readsLeft - 1, buffer)
+      }
+    }
+    val buffer = bufferPool.acquire()
+    try innerRead(BatchReceiveLimit, buffer) finally {
       selector ! ReadInterest
       bufferPool.release(buffer)
     }
@@ -104,7 +111,6 @@ private[io] class UdpConnection(selectorRouter: ActorRef,
       // Datagram channel either sends the whole message, or nothing
       if (writtenBytes == 0) commander ! CommandFailed(send)
       else if (send.wantsAck) commander ! send.ack
-
     } finally {
       udpConn.bufferPool.release(buffer)
       pendingSend = null

akka-actor/src/main/scala/akka/io/UdpFF.scala

@@ -34,7 +34,7 @@ object UdpFF extends ExtensionKey[UdpFFExt] {
                   options: immutable.Traversable[SocketOption] = Nil) extends Command
   case object Unbind extends Command
 
-  case object SimpleSender extends Command
+  case class SimpleSender(options: immutable.Traversable[SocketOption] = Nil) extends Command
 
   case object StopReading extends Command
   case object ResumeReading extends Command

akka-actor/src/main/scala/akka/io/UdpFFListener.scala

@@ -15,6 +15,8 @@ import scala.collection.immutable
 import scala.util.control.NonFatal
 import akka.io.UdpFF.Received
 import akka.io.SelectionHandler.RegisterChannel
+import scala.annotation.tailrec
+import java.nio.ByteBuffer
 
 private[io] class UdpFFListener(selectorRouter: ActorRef,
                                 handler: ActorRef,
@@ -34,6 +36,7 @@ private[io] class UdpFFListener(selectorRouter: ActorRef,
     datagramChannel.configureBlocking(false)
     val socket = datagramChannel.socket
     options.foreach(_.beforeDatagramBind(socket))
+    // FIXME: signal bind failures
     socket.bind(endpoint) // will blow up the actor constructor if the bind fails
     datagramChannel
   }
@@ -60,8 +63,7 @@ private[io] class UdpFFListener(selectorRouter: ActorRef,
   }
 
   def doReceive(handler: ActorRef): Unit = {
-    val buffer = bufferPool.acquire()
-    try {
+    @tailrec def innerReceive(readsLeft: Int, buffer: ByteBuffer) {
       buffer.clear()
       buffer.limit(DirectBufferSize)
 
@@ -69,11 +71,16 @@ private[io] class UdpFFListener(selectorRouter: ActorRef,
         case sender: InetSocketAddress ⇒
           buffer.flip()
           handler ! Received(ByteString(buffer), sender)
-        case _ ⇒ // Ignore
+          if (readsLeft > 0) innerReceive(readsLeft - 1, buffer)
+        case null ⇒ // null means no data was available
       }
+    }
 
+    val buffer = bufferPool.acquire()
+    try innerReceive(BatchReceiveLimit, buffer) finally {
+      bufferPool.release(buffer)
       selector ! ReadInterest
-    } finally bufferPool.release(buffer)
+    }
   }
 
   override def postStop() {

akka-actor/src/main/scala/akka/io/UdpFFManager.scala

@@ -44,17 +44,13 @@ import akka.io.UdpFF._
  */
 private[io] class UdpFFManager(udpFF: UdpFFExt) extends SelectorBasedManager(udpFF.settings, udpFF.settings.NrOfSelectors) {
 
-  // FIXME: fix close overs
-  lazy val anonymousSender: ActorRef = context.actorOf(
-    props = Props(new UdpFFSender(udpFF, selectorPool)),
-    name = "simplesend")
-
   def receive = workerForCommand {
     case Bind(handler, endpoint, options) ⇒
       val commander = sender
       Props(new UdpFFListener(selectorPool, handler, endpoint, commander, udpFF, options))
-  } orElse {
-    case SimpleSender ⇒ anonymousSender forward SimpleSender
+    case SimpleSender(options) ⇒
+      val commander = sender
+      Props(new UdpFFSender(udpFF, options, commander))
   }
 
 }

akka-actor/src/main/scala/akka/io/UdpFFSender.scala

@@ -7,27 +7,34 @@ import akka.actor._
 import java.nio.channels.DatagramChannel
 import akka.io.UdpFF._
 import akka.io.SelectionHandler.{ ChannelRegistered, RegisterChannel }
+import scala.collection.immutable
+import akka.io.Inet.SocketOption
 
 /**
  * Base class for TcpIncomingConnection and TcpOutgoingConnection.
  */
-private[io] class UdpFFSender(val udpFF: UdpFFExt, val selector: ActorRef)
+private[io] class UdpFFSender(val udpFF: UdpFFExt, options: immutable.Traversable[SocketOption], val commander: ActorRef)
   extends Actor with ActorLogging with WithUdpFFSend {
 
+  def selector: ActorRef = context.parent
+
   val channel = {
     val datagramChannel = DatagramChannel.open
     datagramChannel.configureBlocking(false)
+    val socket = datagramChannel.socket
+
+    options foreach { o ⇒
+      o.beforeDatagramBind(socket)
+    }
+
     datagramChannel
   }
   selector ! RegisterChannel(channel, 0)
 
   def receive: Receive = {
-    case ChannelRegistered ⇒ context.become(simpleSendHandlers orElse sendHandlers, discardOld = true)
-    case _                 ⇒ sender ! SimpleSendReady // FIXME: queueing here?
-  }
-
-  def simpleSendHandlers: Receive = {
-    case SimpleSender ⇒ sender ! SimpleSendReady
+    case ChannelRegistered ⇒
+      context.become(sendHandlers, discardOld = true)
+      commander ! SimpleSendReady
   }
 
   override def postStop(): Unit = if (channel.isOpen) channel.close()

akka-actor/src/main/scala/akka/io/WithUdpFFSend.scala

@@ -12,6 +12,9 @@ private[io] trait WithUdpFFSend {
   me: Actor with ActorLogging ⇒
 
   var pendingSend: (Send, ActorRef) = null
+  // If send fails first, we allow a second go after selected writable, but no more. This flag signals that
+  // pending send was already tried once.
+  var retriedSend = false
   def writePending = pendingSend ne null
 
   def selector: ActorRef
@@ -33,7 +36,7 @@ private[io] trait WithUdpFFSend {
 
     case send: Send ⇒
       pendingSend = (send, sender)
-      selector ! WriteInterest
+      doSend()
 
     case ChannelWritable ⇒ doSend()
 
@@ -51,12 +54,19 @@ private[io] trait WithUdpFFSend {
       if (TraceLogging) log.debug("Wrote {} bytes to channel", writtenBytes)
 
       // Datagram channel either sends the whole message, or nothing
-      if (writtenBytes == 0) commander ! CommandFailed(send)
-      else if (send.wantsAck) commander ! send.ack
+      if (writtenBytes == 0) {
+        if (retriedSend) {
+          commander ! CommandFailed(send)
+          retriedSend = false
+          pendingSend = null
+        } else {
+          selector ! WriteInterest
+          retriedSend = true
+        }
+      } else if (send.wantsAck) commander ! send.ack
 
     } finally {
       udpFF.bufferPool.release(buffer)
-      pendingSend = null
     }
 
   }