zhipeng93 commented on a change in pull request #30: URL: https://github.com/apache/flink-ml/pull/30#discussion_r771129221
########## File path: flink-ml-lib/src/main/java/org/apache/flink/ml/common/datastream/AllReduceUtils.java ########## @@ -0,0 +1,286 @@ +/* + * 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.flink.ml.common.datastream; + +import org.apache.flink.api.common.functions.RichFlatMapFunction; +import org.apache.flink.api.common.typeinfo.BasicTypeInfo; +import org.apache.flink.api.common.typeinfo.PrimitiveArrayTypeInfo; +import org.apache.flink.api.common.typeinfo.TypeInformation; +import org.apache.flink.api.java.tuple.Tuple3; +import org.apache.flink.api.java.tuple.Tuple4; +import org.apache.flink.api.java.typeutils.TupleTypeInfo; +import org.apache.flink.streaming.api.datastream.DataStream; +import org.apache.flink.streaming.api.operators.AbstractStreamOperator; +import org.apache.flink.streaming.api.operators.BoundedOneInput; +import org.apache.flink.streaming.api.operators.OneInputStreamOperator; +import org.apache.flink.streaming.runtime.streamrecord.StreamRecord; +import org.apache.flink.util.Collector; + +import java.util.HashMap; +import java.util.Map; + +/** + * Applies all-reduce on a DataStream where each partition contains only one double array. + * + * <p>AllReduce is a communication primitive widely used in MPI. In this implementation, all workers + * do reduce on a partition of the whole data and they all get the final reduce result. In detail, + * we split each double array into chunks of fixed size buffer (4KB by default) and let each subtask + * handle several chunks. + * + * <p>There're mainly three stages: + * <li>1. All workers send their partial data to other workers for reduce. + * <li>2. All workers do reduce on all data it received and then send partial results to others. + * <li>3. All workers merge partial results into final result. + */ +public class AllReduceUtils { + + private static final int TRANSFER_BUFFER_SIZE = 1024 * 4; + Review comment: The `TRANSFER_BUFFER_SIZE ` here is actually `4 * 1024 * DOUBLE.bytes` (32KB), which is consistent with Flink's network buffer size. BTW, I don't think the algorithm developper need to see the `chunk size` here. -- 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: issues-unsubscr...@flink.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
