Merge pull request #20034 from akka/wip-19949-ANQ.count-loop-RK

fix endless loop race condition in NodeQueue, #19949

akka-bench-jmh/src/main/scala/akka/dispatch/NodeQueueBenchmark.scala

@@ -0,0 +1,72 @@
+/**
+ * Copyright (C) 2016 Lightbend Inc. <http://www.lightbend.com>
+ */
+package akka.dispatch
+
+import akka.actor._
+import org.openjdk.jmh.annotations._
+import com.typesafe.config.ConfigFactory
+import java.util.concurrent.TimeUnit
+import scala.concurrent.Await
+import scala.concurrent.duration._
+import akka.testkit.TestProbe
+
+object NodeQueueBenchmark {
+  final val burst = 100000
+  case object Stop
+}
+
+@State(Scope.Benchmark)
+@BenchmarkMode(Array(Mode.Throughput))
+@Fork(2)
+@Warmup(iterations = 5)
+@Measurement(iterations = 10)
+@OutputTimeUnit(TimeUnit.MICROSECONDS)
+class NodeQueueBenchmark {
+  import NodeQueueBenchmark._
+
+  val config = ConfigFactory.parseString("""
+dispatcher {
+  executor = "thread-pool-executor"
+  throughput = 1000
+  thread-pool-executor {
+    fixed-pool-size = 1
+  }
+}
+mailbox {
+  mailbox-type = "akka.dispatch.SingleConsumerOnlyUnboundedMailbox"
+  mailbox-capacity = 1000000
+}
+""").withFallback(ConfigFactory.load())
+  implicit val sys = ActorSystem("ANQ", config)
+  val ref = sys.actorOf(Props(new Actor {
+    def receive = {
+      case Stop => sender() ! Stop
+      case _    =>
+    }
+  }).withDispatcher("dispatcher").withMailbox("mailbox"), "receiver")
+
+  @TearDown
+  def teardown(): Unit = Await.result(sys.terminate(), 5.seconds)
+
+  @TearDown(Level.Invocation)
+  def waitInBetween(): Unit = {
+    val probe = TestProbe()
+    probe.send(ref, Stop)
+    probe.expectMsg(Stop)
+    System.gc()
+    System.gc()
+    System.gc()
+  }
+
+  @Benchmark
+  @OperationsPerInvocation(burst)
+  def send(): Unit = {
+    var todo = burst
+    while (todo > 0) {
+      ref ! "hello"
+      todo -= 1
+    }
+  }
+
+}