org.apache.hadoop.metrics.util.MetricsTimeVaryingRate Maven / Gradle / Ivy
/**
* 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.hadoop.metrics.util;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.metrics.MetricsRecord;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* The MetricsTimeVaryingRate class is for a rate based metric that
* naturally varies over time (e.g. time taken to create a file).
* The rate is averaged at each interval heart beat (the interval
* is set in the metrics config file).
* This class also keeps track of the min and max rates along with
* a method to reset the min-max.
*
*/
@InterfaceAudience.LimitedPrivate({"HDFS", "MapReduce"})
public class MetricsTimeVaryingRate extends MetricsBase {
private static final Log LOG =
LogFactory.getLog("org.apache.hadoop.metrics.util");
static class Metrics {
int numOperations = 0;
long time = 0; // total time or average time
void set(final Metrics resetTo) {
numOperations = resetTo.numOperations;
time = resetTo.time;
}
void reset() {
numOperations = 0;
time = 0;
}
}
static class MinMax {
long minTime = -1;
long maxTime = 0;
void set(final MinMax newVal) {
minTime = newVal.minTime;
maxTime = newVal.maxTime;
}
void reset() {
minTime = -1;
maxTime = 0;
}
void update(final long time) { // update min max
minTime = (minTime == -1) ? time : Math.min(minTime, time);
minTime = Math.min(minTime, time);
maxTime = Math.max(maxTime, time);
}
}
private Metrics currentData;
private Metrics previousIntervalData;
private MinMax minMax;
/**
* Constructor - create a new metric
* @param nam the name of the metrics to be used to publish the metric
* @param registry - where the metrics object will be registered
*/
public MetricsTimeVaryingRate(final String nam, final MetricsRegistry registry, final String description) {
super(nam, description);
currentData = new Metrics();
previousIntervalData = new Metrics();
minMax = new MinMax();
registry.add(nam, this);
}
/**
* Constructor - create a new metric
* @param nam the name of the metrics to be used to publish the metric
* @param registry - where the metrics object will be registered
* A description of {@link #NO_DESCRIPTION} is used
*/
public MetricsTimeVaryingRate(final String nam, MetricsRegistry registry) {
this(nam, registry, NO_DESCRIPTION);
}
/**
* Increment the metrics for numOps operations
* @param numOps - number of operations
* @param time - time for numOps operations
*/
public synchronized void inc(final int numOps, final long time) {
currentData.numOperations += numOps;
currentData.time += time;
long timePerOps = time/numOps;
minMax.update(timePerOps);
}
/**
* Increment the metrics for one operation
* @param time for one operation
*/
public synchronized void inc(final long time) {
currentData.numOperations++;
currentData.time += time;
minMax.update(time);
}
private synchronized void intervalHeartBeat() {
previousIntervalData.numOperations = currentData.numOperations;
previousIntervalData.time = (currentData.numOperations == 0) ?
0 : currentData.time / currentData.numOperations;
currentData.reset();
}
/**
* Push the delta metrics to the mr.
* The delta is since the last push/interval.
*
* Note this does NOT push to JMX
* (JMX gets the info via {@link #getPreviousIntervalAverageTime()} and
* {@link #getPreviousIntervalNumOps()}
*
* @param mr
*/
public synchronized void pushMetric(final MetricsRecord mr) {
intervalHeartBeat();
try {
mr.incrMetric(getName() + "_num_ops", getPreviousIntervalNumOps());
mr.setMetric(getName() + "_avg_time", getPreviousIntervalAverageTime());
} catch (Exception e) {
LOG.info("pushMetric failed for " + getName() + "\n" , e);
}
}
/**
* The number of operations in the previous interval
* @return - ops in prev interval
*/
public synchronized int getPreviousIntervalNumOps() {
return previousIntervalData.numOperations;
}
/**
* The average rate of an operation in the previous interval
* @return - the average rate.
*/
public synchronized long getPreviousIntervalAverageTime() {
return previousIntervalData.time;
}
/**
* The min time for a single operation since the last reset
* {@link #resetMinMax()}
* @return min time for an operation
*/
public synchronized long getMinTime() {
return minMax.minTime;
}
/**
* The max time for a single operation since the last reset
* {@link #resetMinMax()}
* @return max time for an operation
*/
public synchronized long getMaxTime() {
return minMax.maxTime;
}
/**
* Reset the min max values
*/
public synchronized void resetMinMax() {
minMax.reset();
}
}