| /** |
| * 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.mapred; |
| |
| import java.io.IOException; |
| |
| /** |
| * A {@link TaskSelector} implementation that wraps around the default |
| * {@link JobInProgress#obtainNewMapTask(TaskTrackerStatus, int)} and |
| * {@link JobInProgress#obtainNewReduceTask(TaskTrackerStatus, int)} methods |
| * in {@link JobInProgress}, using the default Hadoop locality and speculative |
| * threshold algorithms. |
| */ |
| public class DefaultTaskSelector extends TaskSelector { |
| |
| @Override |
| public int neededSpeculativeMaps(JobInProgress job) { |
| int count = 0; |
| long time = System.currentTimeMillis(); |
| for (TaskInProgress tip: job.maps) { |
| if (tip.isRunning() && tip.canBeSpeculated(time)) { |
| count++; |
| } |
| } |
| return count; |
| } |
| |
| @Override |
| public int neededSpeculativeReduces(JobInProgress job) { |
| int count = 0; |
| long time = System.currentTimeMillis(); |
| double avgProgress = job.getStatus().reduceProgress(); |
| for (TaskInProgress tip: job.reduces) { |
| if (tip.isRunning() && tip.canBeSpeculated(time)) { |
| count++; |
| } |
| } |
| return count; |
| } |
| |
| @Override |
| public Task obtainNewMapTask(TaskTrackerStatus taskTracker, JobInProgress job, |
| int localityLevel) throws IOException { |
| ClusterStatus clusterStatus = taskTrackerManager.getClusterStatus(); |
| int numTaskTrackers = clusterStatus.getTaskTrackers(); |
| return job.obtainNewMapTask(taskTracker, numTaskTrackers, |
| taskTrackerManager.getNumberOfUniqueHosts(), localityLevel); |
| } |
| |
| @Override |
| public Task obtainNewReduceTask(TaskTrackerStatus taskTracker, JobInProgress job) |
| throws IOException { |
| ClusterStatus clusterStatus = taskTrackerManager.getClusterStatus(); |
| int numTaskTrackers = clusterStatus.getTaskTrackers(); |
| return job.obtainNewReduceTask(taskTracker, numTaskTrackers, |
| taskTrackerManager.getNumberOfUniqueHosts()); |
| } |
| |
| } |