pnowojski commented on a change in pull request #14526: URL: https://github.com/apache/flink/pull/14526#discussion_r551395791
########## File path: flink-runtime/src/main/java/org/apache/flink/runtime/metrics/groups/TimeGauge.java ########## @@ -0,0 +1,80 @@ +/* + * 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. + */ + +// ---------------------------------------------------------------------------- +// This class is largely adapted from "com.google.common.base.Preconditions", +// which is part of the "Guava" library. +// +// Because of frequent issues with dependency conflicts, this class was +// added to the Flink code base to reduce dependency on Guava. +// ---------------------------------------------------------------------------- + +package org.apache.flink.runtime.metrics.groups; + +import org.apache.flink.annotation.VisibleForTesting; +import org.apache.flink.metrics.Gauge; +import org.apache.flink.metrics.View; + +/** + * {@link TimeGauge} encapsulate logic of measuring time rates (like idleTime ms/s). In particularly + * it takes care of the case, when single measurement (as defined by {@link #markStart()} and {@link + * #markEnd()}), crosses the boundary of single {@link #update()} interval. Thanks to the {@link + * #markStart()} {@link TimeGauge} can correctly calculate next value in {@link #update()}, even if + * this measurement hasn't not ended ({@link #markEnd()}). + */ +public class TimeGauge implements Gauge<Long>, View { + private long previousCount; + private long currentCount; + private long lastDifference; + private long currentMeasurementStart; + + public synchronized void markStart() { + if (currentMeasurementStart == 0) { + currentMeasurementStart = System.currentTimeMillis(); + } + } + + public synchronized void markEnd() { + if (currentMeasurementStart != 0) { + currentCount += System.currentTimeMillis() - currentMeasurementStart; + currentMeasurementStart = 0; + } + } + + @Override + public synchronized void update() { + if (currentMeasurementStart != 0) { + long now = System.currentTimeMillis(); + currentCount += now - currentMeasurementStart; + currentMeasurementStart = now; + } + lastDifference = (currentCount - previousCount) / UPDATE_INTERVAL_SECONDS; Review comment: I've tried to implement it and it looked like not worth the extra complexity. It would make also testing a bit more complicated. ---------------------------------------------------------------- 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
