sodonnel commented on a change in pull request #3645: URL: https://github.com/apache/hadoop/pull/3645#discussion_r752220174
########## File path: hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/shell/CopyCommandWithMultiThread.java ########## @@ -0,0 +1,157 @@ +/** + * 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.hadoop.fs.shell; + +import java.io.IOException; +import java.util.LinkedList; +import java.util.concurrent.ArrayBlockingQueue; +import java.util.concurrent.ThreadPoolExecutor; +import java.util.concurrent.TimeUnit; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import org.apache.hadoop.classification.VisibleForTesting; + +/** + * Abstract command to enable sub copy commands run with multi-thread. + */ +public abstract class CopyCommandWithMultiThread + extends CommandWithDestination { + + private int threadCount = 1; + private ThreadPoolExecutor executor = null; + private int threadPoolQueueSize = DEFAULT_QUEUE_SIZE; + + public static final int DEFAULT_QUEUE_SIZE = 1024; + public static final int MAX_THREAD_COUNT = + Runtime.getRuntime().availableProcessors() * 2; Review comment: I wonder if we should limit the number of threads like this. Its hard to say if the copy will be CPU bound, or disk / IO bound overall. I guess it is best to avoid having no limit, but I wonder if having 2 * cores would be enough for a small VM trying to put a large dir into the cluster. What do you think? Maybe setting the limit to 4 or 8 * cores would be more flexible for users and they can experiment with their own hardware to find the best setting? -- 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. To unsubscribe, e-mail: common-issues-unsubscr...@hadoop.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: common-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: common-issues-h...@hadoop.apache.org
