squito commented on a change in pull request #23767: [SPARK-26329][CORE] Faster polling of executor memory metrics. URL: https://github.com/apache/spark/pull/23767#discussion_r268739795
########## File path: core/src/main/scala/org/apache/spark/executor/ExecutorMetricsPoller.scala ########## @@ -0,0 +1,210 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.apache.spark.executor + +import java.lang.Long.{MAX_VALUE => LONG_MAX_VALUE} +import java.util.concurrent.{ConcurrentHashMap, TimeUnit} +import java.util.concurrent.atomic.{AtomicLong, AtomicLongArray} + +import scala.collection.mutable.HashMap + +import org.apache.spark.annotation.DeveloperApi +import org.apache.spark.internal.Logging +import org.apache.spark.memory.MemoryManager +import org.apache.spark.metrics.ExecutorMetricType +import org.apache.spark.util.{ThreadUtils, Utils} + +/** + * :: DeveloperApi :: + * A class that polls executor metrics, and tracks their peaks per task and per stage. + * Each executor keeps an instance of this class. + * + * @param memoryManager the memory manager used by the executor. + * @param pollingInterval the polling interval in milliseconds. + */ +@DeveloperApi +private[spark] class ExecutorMetricsPoller( + memoryManager: MemoryManager, + pollingInterval: Long) + extends Logging { + + type StageKey = (Int, Int) + // tuple for Task Count and Metric Peaks + type TCMP = (AtomicLong, AtomicLongArray) + + // Map of (stageId, stageAttemptId) to (count of running tasks, executor metric peaks) + private val stageTCMP = new ConcurrentHashMap[StageKey, TCMP] + + // Map of taskId to executor metric peaks + private val taskMetricPeaks = new ConcurrentHashMap[Long, AtomicLongArray] + + private val poller = + if (pollingInterval > 0) { + ThreadUtils.newDaemonSingleThreadScheduledExecutor("executor-poller") + } else { + null + } + + /** + * Function to poll executor metrics. + * On start, if pollingInterval is positive, this is scheduled to run at that interval. + * Otherwise, this is called by the reportHeartBeat function defined in Executor and passed + * to its Heartbeater. + */ + def poll(): Unit = { + // Note: Task runner threads may update stageTCMP or read from taskMetricPeaks concurrently + // with this function via calls to methods of this class. + + // get the latest values for the metrics + val latestMetrics = ExecutorMetrics.getCurrentMetrics(memoryManager) + + def compareAndUpdate(current: Long, latest: Long): Long = + if (latest > current) latest else current + + def updatePeaks(metrics: AtomicLongArray): Unit = { + (0 until metrics.length).foreach { i => + metrics.getAndAccumulate(i, latestMetrics(i), compareAndUpdate) + } + } + + // for each active stage, update the peaks + stageTCMP.forEachValue(LONG_MAX_VALUE, v => updatePeaks(v._2)) + + // for each running task, update the peaks + taskMetricPeaks.forEachValue(LONG_MAX_VALUE, updatePeaks) + } + + /** Starts the polling thread. */ + def start(): Unit = { + if (poller != null) { + val pollingTask = new Runnable() { + override def run(): Unit = Utils.logUncaughtExceptions(poll()) + } + poller.scheduleAtFixedRate(pollingTask, 0L, pollingInterval, TimeUnit.MILLISECONDS) + } + } + + /** + * Called by Executor#launchTask. + * + * @param taskId the id of the task being launched. + */ + def onTaskLaunch(taskId: Long): Unit = { Review comment: any reason you need this method, instead of just doing this in `onTaskStart`? you have access to the `taskId` from there too, its a bit confusing to have them split up. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
