BewareMyPower commented on code in PR #26163: URL: https://github.com/apache/pulsar/pull/26163#discussion_r3575671541
########## pulsar-common/src/main/java/org/apache/pulsar/common/util/LatencyTracer.java: ########## @@ -0,0 +1,94 @@ +/* + * 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.pulsar.common.util; + +import java.util.ArrayList; +import java.util.Queue; +import java.util.concurrent.CompletableFuture; +import java.util.concurrent.TimeUnit; + +public class LatencyTracer { + + private final Queue<Timepoint> timepoints; + private final NanoTimeSupplier nanoTimeSupplier; + private final long startNs; + + public LatencyTracer(Queue<Timepoint> timepoints, NanoTimeSupplier nanoTimeSupplier) { + this.timepoints = timepoints; + this.nanoTimeSupplier = nanoTimeSupplier; + this.startNs = nanoTimeSupplier.getNanos(); + } + + public <T> CompletableFuture<T> trace(String message, CompletableFuture<T> future) { + if (future.isDone()) { + return future; + } + return future.whenComplete((__, ___) -> trace(message)); + } + + public void trace(String action) { + timepoints.add(new Timepoint(action, nanoTimeSupplier.getNanos())); + } + + public Snapshot getLatency() { + final var timepoints = new ArrayList<>(this.timepoints); + if (timepoints.isEmpty()) { + return new Snapshot(startNs, 0, "total: 0 ms"); + } + final var sb = new StringBuilder(); + final var totalLatencyNs = TimeUnit.NANOSECONDS.toMillis(timepoints.get(timepoints.size() - 1).timeInNanos + - startNs); + sb.append("total: ").append(totalLatencyNs).append(" ms"); + long prevNs = startNs; + for (final var tp : timepoints) { + sb.append(", ").append(tp.name).append(": "); + long latencyMs = TimeUnit.NANOSECONDS.toMillis(tp.timeInNanos - prevNs); + if (latencyMs > 0) { + sb.append(latencyMs).append(" ms"); + } else { + sb.append(TimeUnit.NANOSECONDS.toMicros(tp.timeInNanos - prevNs)).append(" us"); + } + prevNs = tp.timeInNanos; + } + return new Snapshot(prevNs, totalLatencyNs, sb.toString()); + } Review Comment: It's a rare case. Even if it happens, it's still possible to recover the original timestamps from the out-of-order timestamps. -- 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. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
