GCUsageSampler.java

/*
 * Copyright (c) 2001-2017, Zoltan Farkas All Rights Reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * Additionally licensed with:
 *
 * Licensed 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.spf4j.perf.memory;

import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
import gnu.trove.map.TObjectLongMap;
import gnu.trove.map.hash.TObjectLongHashMap;
import java.lang.management.GarbageCollectorMXBean;
import org.spf4j.base.AbstractRunnable;
import org.spf4j.concurrent.DefaultScheduler;
import org.spf4j.perf.MeasurementRecorder;
import org.spf4j.perf.impl.RecorderFactory;
import java.lang.management.ManagementFactory;
import java.util.List;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import org.spf4j.jmx.JmxExport;
import org.spf4j.jmx.Registry;
import org.spf4j.tsdb2.avro.MeasurementType;

/**
 * This class allows you to poll and recordAt to a file the heap committed and heap used for your java process. start
 * data recording by calling the startMemoryUsageSampling method, stop the data recording by calling the method:
 * startMemoryUsageSampling.
 *
 * @author zoly
 */
public final class GCUsageSampler {

  private static final List<GarbageCollectorMXBean> MBEANS = ManagementFactory.getGarbageCollectorMXBeans();
  private static ScheduledFuture<?> samplingFuture;

  static {
    org.spf4j.base.Runtime.queueHook(2, new AbstractRunnable(true) {
      @Override
      public void doRun() {
        stop();
      }
    });
    Registry.export(GCUsageSampler.class);
  }

  private GCUsageSampler() {
  }

  @SuppressFBWarnings("MS_EXPOSE_REP")
  public static List<GarbageCollectorMXBean> getMBEANS() {
    return MBEANS;
  }

  @JmxExport
  public static synchronized void start(@JmxExport("sampleTimeMillis") final int sampleTime) {
    if (samplingFuture == null) {
      final MeasurementRecorder gcUsage
              = RecorderFactory.createDirectRecorder("process.gc_time", "ms", sampleTime, MeasurementType.COUNTER);
      samplingFuture = DefaultScheduler.INSTANCE.scheduleWithFixedDelay(new AbstractRunnable() {

        private final TObjectLongMap lastValues = new TObjectLongHashMap();

        @Override
        public void doRun() {
          synchronized (lastValues) {
            gcUsage.record(getGCTimeDiff(MBEANS, lastValues));
          }
        }
      }, sampleTime, sampleTime, TimeUnit.MILLISECONDS);
    } else {
      throw new IllegalStateException("GC usage sampling already started " + samplingFuture);
    }
  }

  @JmxExport
  public static synchronized void stop() {
    if (samplingFuture != null) {
      samplingFuture.cancel(false);
      samplingFuture = null;
    }
  }

  public static long getGCTimeDiff(final Iterable<GarbageCollectorMXBean> gcBeans, final TObjectLongMap lastValues) {
    long gcTime = 0;
    for (GarbageCollectorMXBean gcBean : gcBeans) {
      long currVal = gcBean.getCollectionTime();
      long prevVal = lastValues.put(gcBean, currVal);
      gcTime += currVal - prevVal;
    }
    return gcTime;
  }

  public static long getGCTime(final Iterable<GarbageCollectorMXBean> gcBeans) {
    long gcTime = 0;
    for (GarbageCollectorMXBean gcBean : gcBeans) {
      gcTime += gcBean.getCollectionTime();
    }
    return gcTime;
  }

  @JmxExport(description = "Get the total GC time in millis since the JVM started")
  public static long getGCTime() {
    return getGCTime(MBEANS);
  }

  @JmxExport
  public static synchronized boolean isStarted() {
    return samplingFuture != null;
  }

}