/**
* 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.tez.mapreduce.processor;
import java.lang.management.GarbageCollectorMXBean;
import java.lang.management.ManagementFactory;
import java.util.List;
import org.apache.tez.common.counters.TezCounter;
import org.apache.tez.common.counters.TezCounters;
import org.apache.tez.common.counters.TaskCounter;
/**
* An updater that tracks the amount of time this task has spent in GC.
*/
class GcTimeUpdater {
private long lastGcMillis = 0;
private List<GarbageCollectorMXBean> gcBeans = null;
TezCounters counters;
public GcTimeUpdater(TezCounters counters) {
this.gcBeans = ManagementFactory.getGarbageCollectorMXBeans();
getElapsedGc(); // Initialize 'lastGcMillis' with the current time spent.
this.counters = counters;
}
/**
* @return the number of milliseconds that the gc has used for CPU
* since the last time this method was called.
*/
protected long getElapsedGc() {
long thisGcMillis = 0;
for (GarbageCollectorMXBean gcBean : gcBeans) {
thisGcMillis += gcBean.getCollectionTime();
}
long delta = thisGcMillis - lastGcMillis;
this.lastGcMillis = thisGcMillis;
return delta;
}
/**
* Increment the gc-elapsed-time counter.
*/
public void incrementGcCounter() {
if (null == counters) {
return; // nothing to do.
}
TezCounter gcCounter =
counters.findCounter(TaskCounter.GC_TIME_MILLIS);
if (null != gcCounter) {
gcCounter.increment(getElapsedGc());
}
}
}