sashapolo commented on code in PR #3068: URL: https://github.com/apache/ignite-3/pull/3068#discussion_r1461740828
########## modules/network/src/main/java/org/apache/ignite/network/NettyWorkersRegistrar.java: ########## @@ -0,0 +1,147 @@ +/* + * 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.ignite.network; + +import static java.util.concurrent.TimeUnit.MILLISECONDS; +import static org.apache.ignite.internal.util.CompletableFutures.nullCompletedFuture; + +import io.netty.channel.nio.NioEventLoopGroup; +import io.netty.util.concurrent.EventExecutor; +import io.netty.util.concurrent.SingleThreadEventExecutor; +import java.util.ArrayList; +import java.util.List; +import java.util.concurrent.CompletableFuture; +import java.util.concurrent.CopyOnWriteArrayList; +import java.util.concurrent.Future; +import java.util.concurrent.ScheduledExecutorService; +import java.util.concurrent.ScheduledFuture; +import org.apache.ignite.internal.manager.IgniteComponent; +import org.apache.ignite.internal.worker.CriticalWorker; +import org.apache.ignite.internal.worker.CriticalWorkerRegistry; +import org.jetbrains.annotations.Nullable; + +/** + * This component is responsible for registering Netty workers with the {@link CriticalWorkerRegistry} and for updating their heartbeats. + */ +public class NettyWorkersRegistrar implements IgniteComponent { + /* + * It seems impossible to instrument tasks executed by Netty event loops, so the strategy we use is to + * send 'heartbeat' tasks to each of the event loops periodically; this tasks just update the heartbeat timestamp + * of the worker corresponding to an event loop. If an event loop's thread is hung, the hearbeat will not + * be updated, and the worker watchdog will treat the event loop worker as blocked. + */ + + private final CriticalWorkerRegistry criticalWorkerRegistry; + + private final ScheduledExecutorService scheduler; + + private final NettyBootstrapFactory bootstrapFactory; + + private final List<NettyWorker> workers = new CopyOnWriteArrayList<>(); + + @Nullable + private volatile ScheduledFuture<?> sendHearbeatsTaskFuture; + + /** + * Constructor. + * + * @param criticalWorkerRegistry Used to register workers representing Netty event loops to detect when their threads are + * blocked. + * @param scheduler Used to schedule periodic tasks. + * @param bootstrapFactory Used to obtain Netty workers. + */ + public NettyWorkersRegistrar( + CriticalWorkerRegistry criticalWorkerRegistry, + ScheduledExecutorService scheduler, + NettyBootstrapFactory bootstrapFactory + ) { + this.criticalWorkerRegistry = criticalWorkerRegistry; + this.scheduler = scheduler; + this.bootstrapFactory = bootstrapFactory; + } + + @Override + public CompletableFuture<Void> start() { + for (NioEventLoopGroup group : bootstrapFactory.eventLoopGroups()) { + registerWorkersFor(group); + } + + sendHearbeatsTaskFuture = scheduler.scheduleAtFixedRate(this::sendHearbeats, 100, 100, MILLISECONDS); + + return nullCompletedFuture(); + } + + private void registerWorkersFor(NioEventLoopGroup group) { + List<NettyWorker> groupWorkers = new ArrayList<>(group.executorCount()); + + for (EventExecutor eventExecutor : group) { + SingleThreadEventExecutor executor = (SingleThreadEventExecutor) eventExecutor; + groupWorkers.add(new NettyWorker(executor)); + } + + for (NettyWorker worker : groupWorkers) { + criticalWorkerRegistry.register(worker); + } + + workers.addAll(groupWorkers); + } + + private void sendHearbeats() { + for (NettyWorker worker : workers) { + worker.sendHeartbeat(); + } + } + + @Override + public void stop() throws Exception { + Future<?> heartBeatsTaskFuture = sendHearbeatsTaskFuture; + if (heartBeatsTaskFuture != null) { + heartBeatsTaskFuture.cancel(false); + } + + for (NettyWorker worker : workers) { + criticalWorkerRegistry.unregister(worker); + } + } + + private static class NettyWorker implements CriticalWorker { + private final SingleThreadEventExecutor eventExecutor; + + private volatile long heartbeatNanos = System.nanoTime(); + + private final Runnable sendHeartbeatTask = () -> heartbeatNanos = System.nanoTime(); Review Comment: Is there a difference if you allocate it here or once inside `sendHeartbeat`? -- This is an automated message from the Apache Git Service. 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