| /* |
| * 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.giraph.utils; |
| |
| import org.apache.giraph.conf.IntConfOption; |
| import org.apache.hadoop.conf.Configuration; |
| |
| import com.sun.management.GcInfo; |
| |
| /** |
| * Tracks last k GC pauses and is able to tell how much time was spent doing |
| * GC since some point in time. Thread safe. |
| */ |
| public class GcTracker { |
| /** How many last gcs to keep */ |
| public static final IntConfOption LAST_GCS_TO_KEEP = |
| new IntConfOption("giraph.lastGcsToKeep", 100, |
| "How many last gcs to keep"); |
| |
| /** Last k GCs which happened */ |
| private final GcInfo[] lastKGcs; |
| /** Next position to write gc to */ |
| private int positionInGcs = 0; |
| |
| /** |
| * Constructor with default number of last gcs to keep |
| */ |
| public GcTracker() { |
| lastKGcs = new GcInfo[LAST_GCS_TO_KEEP.getDefaultValue()]; |
| } |
| |
| /** |
| * Constructor with configuration |
| * |
| * @param conf Configuration |
| */ |
| public GcTracker(Configuration conf) { |
| lastKGcs = new GcInfo[LAST_GCS_TO_KEEP.get(conf)]; |
| } |
| |
| /** |
| * Called to notify gc tracker that gc occurred |
| * |
| * @param gcInfo GC info |
| */ |
| public synchronized void gcOccurred(GcInfo gcInfo) { |
| lastKGcs[positionInGcs] = gcInfo; |
| positionInGcs++; |
| if (positionInGcs == lastKGcs.length) { |
| positionInGcs = 0; |
| } |
| } |
| |
| /** |
| * Check how much time was spent doing gc since some timestamp |
| * |
| * @param timeSinceJvmStarted Timestamp to measure from, you can use |
| * ManagementFactory.getRuntimeMXBean().getUptime() to get it |
| * @return How much time was spent doing gc since that timestamp (if there |
| * were more gcs than we are keeping (LAST_GCS_TO_KEEP) then it will be |
| * partial result) |
| */ |
| public synchronized long gcTimeSpentSince(long timeSinceJvmStarted) { |
| long ret = 0; |
| int currentPosition = positionInGcs; |
| do { |
| currentPosition--; |
| if (currentPosition < 0) { |
| currentPosition = lastKGcs.length - 1; |
| } |
| // If there was no such GC or GC started before the timestamp given, |
| // stop iterating |
| if (lastKGcs[currentPosition] == null || |
| lastKGcs[currentPosition].getStartTime() < timeSinceJvmStarted) { |
| break; |
| } |
| ret += lastKGcs[currentPosition].getDuration(); |
| } while (currentPosition != positionInGcs); |
| return ret; |
| } |
| } |