bipinprasad commented on a change in pull request #3350: URL: https://github.com/apache/storm/pull/3350#discussion_r542780777
########## File path: storm-client/src/jvm/org/apache/storm/metrics2/RateCounter.java ########## @@ -0,0 +1,62 @@ +/** + * 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.storm.metrics2; + +import com.codahale.metrics.Counter; +import com.codahale.metrics.Gauge; + +/** + * A Counter metric that also implements a Gauge to report a 1 minute rate. This class was added as a compromise to + * using a Meter, which has a much larger performance impact. + */ +public class RateCounter implements Gauge<Double> { + private Counter counter; + private double currentRate = 0; + private int time = 0; + private final long[] values; + private final int timeSpanInSeconds; + + RateCounter(StormMetricRegistry metricRegistry, String metricName, String topologyId, + String componentId, int taskId, int workerPort, String streamId) { + counter = metricRegistry.counter(metricName, topologyId, componentId, + taskId, workerPort, streamId); + metricRegistry.gauge(metricName + ".m1_rate", this, topologyId, componentId, streamId, + taskId, workerPort); + this.timeSpanInSeconds = Math.max(60 - (60 % metricRegistry.getRateCounterUpdateIntervalSeconds()), + metricRegistry.getRateCounterUpdateIntervalSeconds()); + this.values = new long[this.timeSpanInSeconds / metricRegistry.getRateCounterUpdateIntervalSeconds() + 1]; + + } + + /** + * Reports the 1 minute rate for the metric. + * @return the rate + */ + @Override + public Double getValue() { + return currentRate; + } + + public void inc(long n) { + counter.inc(n); + } + + /** + * Updates the rate in a background thread by a StormMetricRegistry at a fixed frequency. + */ + void update() { + time = (time + 1) % values.length; + values[time] = counter.getCount(); + currentRate = ((double) (values[time] - values[(time + 1) % values.length]) / timeSpanInSeconds); Review comment: Should this (mod) subtraction be from (valueAtTime - valueAtTimeMinus1), instead of (valueAtTime - valueAtTimePlus1) ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org
