Source code

001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *   http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.apache.reef.util;
020
021import java.lang.management.ManagementFactory;
022import java.lang.management.MemoryPoolMXBean;
023import java.util.List;
024
025/**
026 * Utility class to report current and peak memory
027 * usage. Structured to be used while logging. Is
028 * useful for debugging memory issues
029 */
030public final class MemoryUtils {
031
032  private static final int MBs = 1024 * 1024;
033
034  private MemoryUtils() {
035  }
036
037  public static String memPoolNames() {
038    final List<MemoryPoolMXBean> memoryPoolMXBeans = ManagementFactory.getMemoryPoolMXBeans();
039    final StringBuilder output = new StringBuilder();
040    for (final MemoryPoolMXBean bean : memoryPoolMXBeans) {
041      output.append(bean.getName());
042      output.append(",");
043    }
044    output.deleteCharAt(output.length() - 1);
045    return output.toString();
046  }
047
048  public static long currentEdenMemoryUsageMB() {
049    return currentMemoryUsage("eden");
050  }
051
052  public static long currentOldMemoryUsageMB() {
053    return currentMemoryUsage("old");
054  }
055
056  public static long currentPermMemoryUsageMB() {
057    return currentMemoryUsage("perm");
058  }
059
060  private static long currentMemoryUsage(final String name) {
061    final List<MemoryPoolMXBean> memoryPoolMXBeans = ManagementFactory.getMemoryPoolMXBeans();
062    for (final MemoryPoolMXBean bean : memoryPoolMXBeans) {
063      if (bean.getName().toLowerCase().indexOf(name) != -1) {
064        return bean.getUsage().getUsed() / MBs;
065      }
066    }
067    return 0;
068  }
069
070  public static long peakEdenMemoryUsageMB() {
071    return peakMemoryUsage("eden");
072  }
073
074  public static long peakOldMemoryUsageMB() {
075    return peakMemoryUsage("old");
076  }
077
078  public static long peakPermMemoryUsageMB() {
079    return peakMemoryUsage("perm");
080  }
081
082  private static long peakMemoryUsage(final String name) {
083    final List<MemoryPoolMXBean> memoryPoolMXBeans = ManagementFactory.getMemoryPoolMXBeans();
084    for (final MemoryPoolMXBean bean : memoryPoolMXBeans) {
085      if (bean.getName().toLowerCase().indexOf(name) != -1) {
086        return bean.getPeakUsage().getUsed() / MBs;
087      }
088    }
089    return 0;
090  }
091
092  public static void resetPeakUsage() {
093    final List<MemoryPoolMXBean> memoryPoolMXBeans = ManagementFactory.getMemoryPoolMXBeans();
094    for (final MemoryPoolMXBean memoryPoolMXBean : memoryPoolMXBeans) {
095      memoryPoolMXBean.resetPeakUsage();
096    }
097  }
098
099  public static void main(final String[] args) {
100    System.out.println(memPoolNames());
101    {
102      final byte[] b = new byte[1 << 24];
103      System.out.println(currentEdenMemoryUsageMB()
104          + "," + currentOldMemoryUsageMB()
105          + "," + currentPermMemoryUsageMB());
106    }
107
108    System.gc();
109    System.out.println(currentEdenMemoryUsageMB()
110        + "," + currentOldMemoryUsageMB()
111        + "," + currentPermMemoryUsageMB());
112    System.out.println(peakEdenMemoryUsageMB()
113        + "," + peakOldMemoryUsageMB()
114        + "," + peakPermMemoryUsageMB());
115    resetPeakUsage();
116    System.out.println(peakEdenMemoryUsageMB()
117        + "," + peakOldMemoryUsageMB()
118        + "," + peakPermMemoryUsageMB());
119  }
120}