Ngone51 commented on a change in pull request #30312: URL: https://github.com/apache/spark/pull/30312#discussion_r532383387
########## File path: core/src/main/scala/org/apache/spark/shuffle/ShuffleBlockPusher.scala ########## @@ -0,0 +1,462 @@ +/* + * 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.shuffle + +import java.io.File +import java.net.ConnectException +import java.nio.ByteBuffer +import java.util.concurrent.ExecutorService + +import scala.collection.mutable.{ArrayBuffer, HashMap, HashSet, Queue} + +import com.google.common.base.Throwables + +import org.apache.spark.{ShuffleDependency, SparkConf, SparkEnv} +import org.apache.spark.annotation.Since +import org.apache.spark.internal.Logging +import org.apache.spark.internal.config._ +import org.apache.spark.launcher.SparkLauncher +import org.apache.spark.network.buffer.{FileSegmentManagedBuffer, ManagedBuffer, NioManagedBuffer} +import org.apache.spark.network.netty.SparkTransportConf +import org.apache.spark.network.shuffle.BlockFetchingListener +import org.apache.spark.network.shuffle.ErrorHandler.BlockPushErrorHandler +import org.apache.spark.network.util.TransportConf +import org.apache.spark.shuffle.ShuffleBlockPusher._ +import org.apache.spark.storage.{BlockId, BlockManagerId, ShufflePushBlockId} +import org.apache.spark.util.{ThreadUtils, Utils} + +/** + * Used for pushing shuffle blocks to remote shuffle services when push shuffle is enabled. + * When push shuffle is enabled, it is created after the shuffle writer finishes writing the shuffle + * file and initiates the block push process. + * + * @param dataFile mapper generated shuffle data file + * @param partitionLengths array of shuffle block size so we can tell shuffle block + * boundaries within the shuffle file + * @param dep shuffle dependency to get shuffle ID and the location of remote shuffle + * services to push local shuffle blocks + * @param partitionId map index of the shuffle map task + * @param conf spark configuration + */ +@Since("3.1.0") +private[spark] class ShuffleBlockPusher( + dataFile: File, + partitionLengths: Array[Long], + dep: ShuffleDependency[_, _, _], + partitionId: Int, + conf: SparkConf) extends Logging { + private[this] var maxBytesInFlight = 0L + private[this] var maxReqsInFlight = 0 + private[this] var maxBlocksInFlightPerAddress = 0 + private[this] var bytesInFlight = 0L + private[this] var reqsInFlight = 0 + private[this] val numBlocksInFlightPerAddress = new HashMap[BlockManagerId, Int]() + private[this] val deferredPushRequests = new HashMap[BlockManagerId, Queue[PushRequest]]() + private[this] val pushRequests = new Queue[PushRequest] + private[this] val errorHandler = createErrorHandler() + private[this] val unreachableBlockMgrs = new HashSet[BlockManagerId]() + + // VisibleForTesting + private[shuffle] def createErrorHandler(): BlockPushErrorHandler = { + new BlockPushErrorHandler() { + // For a connection exception against a particular host, we will stop pushing any + // blocks to just that host and continue push blocks to other hosts. So, here push of + // all blocks will only stop when it is "Too Late". Also see updateStateAndCheckIfPushMore. + override def shouldRetryError(t: Throwable): Boolean = { + // If the block is too late, there is no need to retry it + !Throwables.getStackTraceAsString(t).contains(BlockPushErrorHandler.TOO_LATE_MESSAGE_SUFFIX) + } + } + } + + private[shuffle] def initiateBlockPush(): Unit = { + val numPartitions = dep.partitioner.numPartitions + val transportConf = SparkTransportConf.fromSparkConf(conf, "shuffle") + + val maxBlockSizeToPush = conf.get(SHUFFLE_MAX_BLOCK_SIZE_TO_PUSH) * 1024 + val maxBlockBatchSize = conf.get(SHUFFLE_MAX_BLOCK_BATCH_SIZE_FOR_PUSH) * 1024 * 1024 + val mergerLocs = dep.getMergerLocs.map(loc => BlockManagerId("", loc.host, loc.port)) + + maxBytesInFlight = conf.getSizeAsMb("spark.reducer.maxSizeInFlight", "48m") * 1024 * 1024 + maxReqsInFlight = conf.getInt("spark.reducer.maxReqsInFlight", Int.MaxValue) + maxBlocksInFlightPerAddress = conf.get(REDUCER_MAX_BLOCKS_IN_FLIGHT_PER_ADDRESS) + + val requests = prepareBlockPushRequests(numPartitions, partitionId, dep.shuffleId, dataFile, + partitionLengths, mergerLocs, transportConf, maxBlockSizeToPush, maxBlockBatchSize) + // Randomize the orders of the PushRequest, so different mappers pushing blocks at the same + // time won't be pushing the same ranges of shuffle partitions. + pushRequests ++= Utils.randomize(requests) + + submitTask(() => { + pushUpToMax() + }) + } + + /** + * Triggers the push. It's a separate method for testing. + * VisibleForTesting + */ + protected def submitTask(task: Runnable): Unit = { + if (BLOCK_PUSHER_POOL != null) { + BLOCK_PUSHER_POOL.execute(task) + } + } + + /** + * Since multiple netty client threads could potentially be calling pushUpToMax for the same + * mapper, we synchronize access to this method so that only one thread can push blocks for + * a given mapper. This helps to simplify access to the shared states. The down side of this + * is that we could unnecessarily block other mappers' block pushes if all netty client threads + * are occupied by block pushes from the same mapper. + * + * This code is similar to ShuffleBlockFetcherIterator#fetchUpToMaxBytes in how it throttles + * the data transfer between shuffle client/server. + */ + private def pushUpToMax(): Unit = synchronized { + // Process any outstanding deferred push requests if possible. + if (deferredPushRequests.nonEmpty) { + for ((remoteAddress, defReqQueue) <- deferredPushRequests) { + while (isRemoteBlockPushable(defReqQueue) && + !isRemoteAddressMaxedOut(remoteAddress, defReqQueue.front)) { + val request = defReqQueue.dequeue() + logDebug(s"Processing deferred push request for $remoteAddress with " + + s"${request.blocks.length} blocks") + sendRequest(request) + if (defReqQueue.isEmpty) { + deferredPushRequests -= remoteAddress + } + } + } + } + + // Process any regular push requests if possible. + while (isRemoteBlockPushable(pushRequests)) { + val request = pushRequests.dequeue() + val remoteAddress = request.address + if (isRemoteAddressMaxedOut(remoteAddress, request)) { + logDebug(s"Deferring push request for $remoteAddress with ${request.blocks.size} blocks") + val defReqQueue = deferredPushRequests.getOrElse(remoteAddress, new Queue[PushRequest]()) + defReqQueue.enqueue(request) + deferredPushRequests(remoteAddress) = defReqQueue + } else { + sendRequest(request) + } + } + + def isRemoteBlockPushable(pushReqQueue: Queue[PushRequest]): Boolean = { + pushReqQueue.nonEmpty && + (bytesInFlight == 0 || + (reqsInFlight + 1 <= maxReqsInFlight && + bytesInFlight + pushReqQueue.front.size <= maxBytesInFlight)) + } + + // Checks if sending a new push request will exceed the max no. of blocks being pushed to a + // given remote address. + def isRemoteAddressMaxedOut(remoteAddress: BlockManagerId, request: PushRequest): Boolean = { + (numBlocksInFlightPerAddress.getOrElse(remoteAddress, 0) + + request.blocks.size) > maxBlocksInFlightPerAddress + } + } + + /** + * Push blocks to remote shuffle server. The callback listener will invoke #pushUpToMax again + * to trigger pushing the next batch of blocks once some block transfer is done in the current + * batch. This way, we decouple the map task from the block push process, since it is netty + * client thread instead of task execution thread which takes care of majority of the block + * pushes. + */ + private def sendRequest(request: PushRequest): Unit = { + bytesInFlight = bytesInFlight + request.size + reqsInFlight = reqsInFlight + 1 + numBlocksInFlightPerAddress(request.address) = numBlocksInFlightPerAddress.getOrElseUpdate( + request.address, 0) + request.blocks.length + + val sizeMap = request.blocks.map { case (blockId, size) => (blockId.toString, size) }.toMap + val address = request.address + val blockIds = request.blocks.map(_._1.toString) + val remainingBlocks = new HashSet[String]() ++= blockIds + + val blockPushListener = new BlockFetchingListener { + // Initiating a connection and pushing blocks to a remote shuffle service is always handled by + // the block-push-threads. We should not initiate the connection creation in the + // blockPushListener callbacks which are invoked by the netty eventloop because: + // 1. TrasportClient.createConnection(...) blocks for connection to be established and it's + // recommended to avoid any blocking operations in the eventloop; + // 2. The actual connection creation is a task that gets added to the task queue of another + // eventloop which could have eventloops eventually blocking each other. + // Once the blockPushListener is notified of the block push success or failure, we + // just delegate it to block-push-threads. + def handleResult(result: PushResult): Unit = { + submitTask(() => { + if (updateStateAndCheckIfPushMore( + sizeMap(result.blockId), address, remainingBlocks, result)) { + pushUpToMax() + } + }) + } + + override def onBlockFetchSuccess(blockId: String, data: ManagedBuffer): Unit = { + logTrace(s"Push for block $blockId to $address successful.") + handleResult(PushResult(blockId, null)) + } + + override def onBlockFetchFailure(blockId: String, exception: Throwable): Unit = { + // check the message or it's cause to see it needs to be logged. + if (!errorHandler.shouldLogError(exception)) { + logTrace(s"Pushing block $blockId to $address failed.", exception) + } else { + logWarning(s"Pushing block $blockId to $address failed.", exception) + } + handleResult(PushResult(blockId, exception)) + } + } + SparkEnv.get.blockManager.blockStoreClient.pushBlocks( + address.host, address.port, blockIds.toArray, + sliceReqBufferIntoBlockBuffers(request.reqBuffer, request.blocks.map(_._2)), + blockPushListener) + } + + /** + * Given the ManagedBuffer representing all the continuous blocks inside the shuffle data file + * for a PushRequest and an array of individual block sizes, load the buffer from disk into + * memory and slice it into multiple smaller buffers representing each block. + * + * With nio ByteBuffer, the individual block buffers share data with the initial in memory + * buffer loaded from disk. Thus only one copy of the block data is kept in memory. + * @param reqBuffer A {{FileSegmentManagedBuffer}} representing all the continuous blocks in + * the shuffle data file for a PushRequest + * @param blockSizes Array of block sizes + * @return Array of in memory buffer for each individual block + */ + private def sliceReqBufferIntoBlockBuffers( + reqBuffer: ManagedBuffer, + blockSizes: Seq[Long]): Array[ManagedBuffer] = { + if (blockSizes.size == 1) { + Array(reqBuffer) + } else { + val inMemoryBuffer = reqBuffer.nioByteBuffer() + val blockOffsets = new Array[Long](blockSizes.size) + var offset = 0L + for (index <- blockSizes.indices) { + blockOffsets(index) = offset + offset += blockSizes(index) + } + blockOffsets.zip(blockSizes).map { + case (offset, size) => + new NioManagedBuffer(inMemoryBuffer.duplicate() Review comment: I thought `duplicate()` would duplicate the memory usage at the same time. But seems like they still share the same buffer. 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