[SPARK-20863] Add metrics/instrumentation to LiveListenerBus

core/src/main/scala/org/apache/spark/SparkContext.scala

@@ -195,6 +195,7 @@ class SparkContext(config: SparkConf) extends Logging {
   private var _conf: SparkConf = _
   private var _eventLogDir: Option[URI] = None
   private var _eventLogCodec: Option[String] = None
+  private var _listenerBus: LiveListenerBus = _
   private var _env: SparkEnv = _
   private var _jobProgressListener: JobProgressListener = _
   private var _statusTracker: SparkStatusTracker = _
@@ -247,7 +248,7 @@ class SparkContext(config: SparkConf) extends Logging {
   def isStopped: Boolean = stopped.get()
 
   // An asynchronous listener bus for Spark events
-  private[spark] val listenerBus = new LiveListenerBus(this)
+  private[spark] def listenerBus: LiveListenerBus = _listenerBus
 
   // This function allows components created by SparkEnv to be mocked in unit tests:
   private[spark] def createSparkEnv(
@@ -423,6 +424,8 @@ class SparkContext(config: SparkConf) extends Logging {
 
     if (master == "yarn" && deployMode == "client") System.setProperty("SPARK_YARN_MODE", "true")
 
+    _listenerBus = new LiveListenerBus(_conf)
+
     // "_jobProgressListener" should be set up before creating SparkEnv because when creating
     // "SparkEnv", some messages will be posted to "listenerBus" and we should not miss them.
     _jobProgressListener = new JobProgressListener(_conf)
@@ -2388,7 +2391,7 @@ class SparkContext(config: SparkConf) extends Logging {
         }
     }
 
-    listenerBus.start()
+    listenerBus.start(this, _env.metricsSystem)
     _listenerBusStarted = true
   }
 

core/src/main/scala/org/apache/spark/scheduler/LiveListenerBus.scala

@@ -20,10 +20,16 @@ package org.apache.spark.scheduler
 import java.util.concurrent._
 import java.util.concurrent.atomic.{AtomicBoolean, AtomicLong}
 
+import scala.collection.mutable
 import scala.util.DynamicVariable
 
-import org.apache.spark.SparkContext
+import com.codahale.metrics.{Counter, Gauge, MetricRegistry, Timer}
+
+import org.apache.spark.{SparkConf, SparkContext}
+import org.apache.spark.internal.Logging
 import org.apache.spark.internal.config._
+import org.apache.spark.metrics.MetricsSystem
+import org.apache.spark.metrics.source.Source
 import org.apache.spark.util.Utils
 
 /**
@@ -33,15 +39,20 @@ import org.apache.spark.util.Utils
  * has started will events be actually propagated to all attached listeners. This listener bus
  * is stopped when `stop()` is called, and it will drop further events after stopping.
  */
-private[spark] class LiveListenerBus(val sparkContext: SparkContext) extends SparkListenerBus {
+private[spark] class LiveListenerBus(conf: SparkConf) extends SparkListenerBus {
+
   self =>
 
   import LiveListenerBus._
 
+  private var sparkContext: SparkContext = _
+
   // Cap the capacity of the event queue so we get an explicit error (rather than
   // an OOM exception) if it's perpetually being added to more quickly than it's being drained.
-  private lazy val eventQueue = new LinkedBlockingQueue[SparkListenerEvent](
-    sparkContext.conf.get(LISTENER_BUS_EVENT_QUEUE_CAPACITY))
+  private val eventQueue =
+    new LinkedBlockingQueue[SparkListenerEvent](conf.get(LISTENER_BUS_EVENT_QUEUE_CAPACITY))
+
+  private[spark] val metrics = new LiveListenerBusMetrics(eventQueue)
 
   // Indicate if `start()` is called
   private val started = new AtomicBoolean(false)
@@ -67,6 +78,7 @@ private[spark] class LiveListenerBus(val sparkContext: SparkContext) extends Spa
     setDaemon(true)
     override def run(): Unit = Utils.tryOrStopSparkContext(sparkContext) {
       LiveListenerBus.withinListenerThread.withValue(true) {
+        val timer = metrics.eventProcessingTime
         while (true) {
           eventLock.acquire()
           self.synchronized {
@@ -82,7 +94,12 @@ private[spark] class LiveListenerBus(val sparkContext: SparkContext) extends Spa
               }
               return
             }
-            postToAll(event)
+            val timerContext = timer.time()
+            try {
+              postToAll(event)
+            } finally {
+              timerContext.stop()
+            }
           } finally {
             self.synchronized {
               processingEvent = false
@@ -93,16 +110,23 @@ private[spark] class LiveListenerBus(val sparkContext: SparkContext) extends Spa
     }
   }
 
+  override protected def getTimer(listener: SparkListenerInterface): Option[Timer] = {
+    metrics.getTimerForListenerClass(listener.getClass.asSubclass(classOf[SparkListenerInterface]))
+  }
+
   /**
    * Start sending events to attached listeners.
    *
    * This first sends out all buffered events posted before this listener bus has started, then
    * listens for any additional events asynchronously while the listener bus is still running.
    * This should only be called once.
    *
+   * @param sc Used to stop the SparkContext in case the listener thread dies.
    */
-  def start(): Unit = {
+  def start(sc: SparkContext, metricsSystem: MetricsSystem): Unit = {
     if (started.compareAndSet(false, true)) {
+      sparkContext = sc
+      metricsSystem.registerSource(metrics)
       listenerThread.start()
     } else {
       throw new IllegalStateException(s"$name already started!")
@@ -115,12 +139,12 @@ private[spark] class LiveListenerBus(val sparkContext: SparkContext) extends Spa
       logError(s"$name has already stopped! Dropping event $event")
       return
     }
+    metrics.numEventsPosted.inc()
     val eventAdded = eventQueue.offer(event)
     if (eventAdded) {
       eventLock.release()
     } else {
       onDropEvent(event)
-      droppedEventsCounter.incrementAndGet()
     }
 
     val droppedEvents = droppedEventsCounter.get
@@ -200,6 +224,8 @@ private[spark] class LiveListenerBus(val sparkContext: SparkContext) extends Spa
    * Note: `onDropEvent` can be called in any thread.
    */
   def onDropEvent(event: SparkListenerEvent): Unit = {
+    metrics.numDroppedEvents.inc()
+    droppedEventsCounter.incrementAndGet()
     if (logDroppedEvent.compareAndSet(false, true)) {
       // Only log the following message once to avoid duplicated annoying logs.
       logError("Dropping SparkListenerEvent because no remaining room in event queue. " +
@@ -217,3 +243,61 @@ private[spark] object LiveListenerBus {
   val name = "SparkListenerBus"
 }
 
+private[spark]
+class LiveListenerBusMetrics(queue: LinkedBlockingQueue[_]) extends Source with Logging {
+  override val sourceName: String = "LiveListenerBus"
+  override val metricRegistry: MetricRegistry = new MetricRegistry
+
+  /**
+   * The total number of events posted to the LiveListenerBus. This is a count of the total number
+   * of events which have been produced by the application and sent to the listener bus, NOT a
+   * count of the number of events which have been processed and delivered to listeners (or dropped
+   * without being delivered).
+   */
+  val numEventsPosted: Counter = metricRegistry.counter(MetricRegistry.name("numEventsPosted"))
+
+  /**
+   * The total number of events that were dropped without being delivered to listeners.
+   */
+  val numDroppedEvents: Counter = metricRegistry.counter(MetricRegistry.name("numEventsDropped"))
+
+  /**
+   * The amount of time taken to post a single event to all listeners.
+   */
+  val eventProcessingTime: Timer = metricRegistry.timer(MetricRegistry.name("eventProcessingTime"))
+
+  /**
+   * The number of messages waiting in the queue.
+   */
+  val queueSize: Gauge[Int] = {
+    metricRegistry.register(MetricRegistry.name("queueSize"), new Gauge[Int]{
+      override def getValue: Int = queue.size()
+    })
+  }
+
+  // Guarded by synchronization.
+  private val perListenerClassTimers = mutable.Map[String, Timer]()
+
+  /**
+   * Returns a timer tracking the processing time of the given listener class.
+   * events processed by that listener. This method is thread-safe.
+   */
+  def getTimerForListenerClass(cls: Class[_ <: SparkListenerInterface]): Option[Timer] = {
+    synchronized {
+      val className = cls.getName
+      val maxTimed = 128
+      perListenerClassTimers.get(className).orElse {
+        if (perListenerClassTimers.size == maxTimed) {
+          logError(s"Not measuring processing time for listener class $className because a " +
+            s"maximum of $maxTimed listener classes are already timed.")
+          None
+        } else {
+          perListenerClassTimers(className) =
+            metricRegistry.timer(MetricRegistry.name("listenerProcessingTime", className))
+          perListenerClassTimers.get(className)
+        }
+      }
+    }
+  }
+}
+

core/src/main/scala/org/apache/spark/util/ListenerBus.scala

@@ -23,29 +23,41 @@ import scala.collection.JavaConverters._
 import scala.reflect.ClassTag
 import scala.util.control.NonFatal
 
+import com.codahale.metrics.Timer
+
 import org.apache.spark.internal.Logging
 
 /**
  * An event bus which posts events to its listeners.
  */
 private[spark] trait ListenerBus[L <: AnyRef, E] extends Logging {
 
+  private[this] val listenersPlusTimers = new CopyOnWriteArrayList[(L, Timer)]
+
   // Marked `private[spark]` for access in tests.
-  private[spark] val listeners = new CopyOnWriteArrayList[L]
+  private[spark] def listeners = listenersPlusTimers.asScala.map(_._1).asJava
+
+  /**
+   * Returns a CodaHale metrics Timer for measuring the listener's event processing time.
+   * This method is intended to be overridden by subclasses.
+   */
+  protected def getTimer(listener: L): Option[Timer] = None
 
   /**
    * Add a listener to listen events. This method is thread-safe and can be called in any thread.
    */
   final def addListener(listener: L): Unit = {
-    listeners.add(listener)
+    listenersPlusTimers.add((listener, getTimer(listener).orNull))
   }
 
   /**
    * Remove a listener and it won't receive any events. This method is thread-safe and can be called
    * in any thread.
    */
   final def removeListener(listener: L): Unit = {
-    listeners.remove(listener)
+    listenersPlusTimers.asScala.find(_._1 eq listener).foreach { listenerAndTimer =>
+      listenersPlusTimers.remove(listenerAndTimer)
+    }
   }
 
   /**
@@ -56,14 +68,25 @@ private[spark] trait ListenerBus[L <: AnyRef, E] extends Logging {
     // JavaConverters can create a JIterableWrapper if we use asScala.
     // However, this method will be called frequently. To avoid the wrapper cost, here we use
     // Java Iterator directly.
-    val iter = listeners.iterator
+    val iter = listenersPlusTimers.iterator
     while (iter.hasNext) {
-      val listener = iter.next()
+      val listenerAndMaybeTimer = iter.next()
+      val listener = listenerAndMaybeTimer._1
+      val maybeTimer = listenerAndMaybeTimer._2
+      val maybeTimerContext = if (maybeTimer != null) {
+        maybeTimer.time()
+      } else {
+        null
+      }
       try {
         doPostEvent(listener, event)
       } catch {
         case NonFatal(e) =>
           logError(s"Listener ${Utils.getFormattedClassName(listener)} threw an exception", e)
+      } finally {
+        if (maybeTimerContext != null) {
+          maybeTimerContext.stop()
+        }
       }
     }
   }

core/src/test/scala/org/apache/spark/scheduler/EventLoggingListenerSuite.scala

@@ -25,12 +25,14 @@ import scala.io.Source
 
 import org.apache.hadoop.fs.Path
 import org.json4s.jackson.JsonMethods._
+import org.mockito.Mockito
 import org.scalatest.BeforeAndAfter
 
 import org.apache.spark._
 import org.apache.spark.deploy.SparkHadoopUtil
 import org.apache.spark.internal.Logging
 import org.apache.spark.io._
+import org.apache.spark.metrics.MetricsSystem
 import org.apache.spark.util.{JsonProtocol, Utils}
 
 /**
@@ -155,17 +157,18 @@ class EventLoggingListenerSuite extends SparkFunSuite with LocalSparkContext wit
     extraConf.foreach { case (k, v) => conf.set(k, v) }
     val logName = compressionCodec.map("test-" + _).getOrElse("test")
     val eventLogger = new EventLoggingListener(logName, None, testDirPath.toUri(), conf)
-    val listenerBus = new LiveListenerBus(sc)
+    val listenerBus = new LiveListenerBus(conf)
     val applicationStart = SparkListenerApplicationStart("Greatest App (N)ever", None,
       125L, "Mickey", None)
     val applicationEnd = SparkListenerApplicationEnd(1000L)
 
     // A comprehensive test on JSON de/serialization of all events is in JsonProtocolSuite
     eventLogger.start()
-    listenerBus.start()
+    listenerBus.start(Mockito.mock(classOf[SparkContext]), Mockito.mock(classOf[MetricsSystem]))
     listenerBus.addListener(eventLogger)
     listenerBus.postToAll(applicationStart)
     listenerBus.postToAll(applicationEnd)
+    listenerBus.stop()
     eventLogger.stop()
 
     // Verify file contains exactly the two events logged