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 BYTES_IN_MEGABYTE = 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() / BYTES_IN_MEGABYTE;
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() / BYTES_IN_MEGABYTE;
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  /**
100   * Returns the total amount of physical memory on the current machine in megabytes.
101   *
102   * Some JVMs may not support the underlying API call.
103   *
104   * @return memory size in MB if the call succeeds; -1 otherwise
105   */
106  public static int getTotalPhysicalMemorySizeInMB() {
107
108    int memorySizeInMB;
109    try {
110      long memorySizeInBytes = ((com.sun.management.OperatingSystemMXBean) ManagementFactory
111                    .getOperatingSystemMXBean()).getTotalPhysicalMemorySize();
112
113      memorySizeInMB = (int) (memorySizeInBytes / BYTES_IN_MEGABYTE);
114    } catch (Exception e) {
115      memorySizeInMB = -1;
116    }
117
118    return memorySizeInMB;
119  }
120
121  public static void main(final String[] args) {
122    System.out.println(memPoolNames());
123
124    final byte[] b = new byte[1 << 24];
125    System.out.println(currentEdenMemoryUsageMB()
126        + "," + currentOldMemoryUsageMB()
127        + "," + currentPermMemoryUsageMB());
128
129    System.gc();
130    System.out.println(currentEdenMemoryUsageMB()
131        + "," + currentOldMemoryUsageMB()
132        + "," + currentPermMemoryUsageMB());
133    System.out.println(peakEdenMemoryUsageMB()
134        + "," + peakOldMemoryUsageMB()
135        + "," + peakPermMemoryUsageMB());
136    resetPeakUsage();
137    System.out.println(peakEdenMemoryUsageMB()
138        + "," + peakOldMemoryUsageMB()
139        + "," + peakPermMemoryUsageMB());
140  }
141}