| #region Copyright notice and license |
| |
| // Copyright 2015 gRPC authors. |
| // |
| // Licensed 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. |
| |
| #endregion |
| |
| using System; |
| using System.Collections.Generic; |
| using System.Linq; |
| using System.Threading; |
| using System.Threading.Tasks; |
| using Grpc.Core.Logging; |
| using Grpc.Core.Profiling; |
| using Grpc.Core.Utils; |
| |
| namespace Grpc.Core.Internal |
| { |
| /// <summary> |
| /// Pool of threads polling on a set of completions queues. |
| /// </summary> |
| internal class GrpcThreadPool |
| { |
| static readonly ILogger Logger = GrpcEnvironment.Logger.ForType<GrpcThreadPool>(); |
| const int FinishContinuationsSleepMillis = 10; |
| const int MaxFinishContinuationsSleepTotalMillis = 10000; |
| |
| readonly GrpcEnvironment environment; |
| readonly object myLock = new object(); |
| readonly List<Thread> threads = new List<Thread>(); |
| readonly int poolSize; |
| readonly int completionQueueCount; |
| readonly bool inlineHandlers; |
| readonly WaitCallback runCompletionQueueEventCallbackSuccess; |
| readonly WaitCallback runCompletionQueueEventCallbackFailure; |
| readonly AtomicCounter queuedContinuationCounter = new AtomicCounter(); |
| |
| readonly List<BasicProfiler> threadProfilers = new List<BasicProfiler>(); // profilers assigned to threadpool threads |
| |
| bool stopRequested; |
| |
| IReadOnlyCollection<CompletionQueueSafeHandle> completionQueues; |
| |
| /// <summary> |
| /// Creates a thread pool threads polling on a set of completions queues. |
| /// </summary> |
| /// <param name="environment">Environment.</param> |
| /// <param name="poolSize">Pool size.</param> |
| /// <param name="completionQueueCount">Completion queue count.</param> |
| /// <param name="inlineHandlers">Handler inlining.</param> |
| public GrpcThreadPool(GrpcEnvironment environment, int poolSize, int completionQueueCount, bool inlineHandlers) |
| { |
| this.environment = environment; |
| this.poolSize = poolSize; |
| this.completionQueueCount = completionQueueCount; |
| this.inlineHandlers = inlineHandlers; |
| GrpcPreconditions.CheckArgument(poolSize >= completionQueueCount, |
| "Thread pool size cannot be smaller than the number of completion queues used."); |
| |
| this.runCompletionQueueEventCallbackSuccess = new WaitCallback((callback) => RunCompletionQueueEventCallback((IOpCompletionCallback) callback, true)); |
| this.runCompletionQueueEventCallbackFailure = new WaitCallback((callback) => RunCompletionQueueEventCallback((IOpCompletionCallback) callback, false)); |
| } |
| |
| public void Start() |
| { |
| lock (myLock) |
| { |
| GrpcPreconditions.CheckState(completionQueues == null, "Already started."); |
| completionQueues = CreateCompletionQueueList(environment, completionQueueCount); |
| |
| for (int i = 0; i < poolSize; i++) |
| { |
| var optionalProfiler = i < threadProfilers.Count ? threadProfilers[i] : null; |
| threads.Add(CreateAndStartThread(i, optionalProfiler)); |
| } |
| } |
| } |
| |
| public Task StopAsync() |
| { |
| lock (myLock) |
| { |
| GrpcPreconditions.CheckState(!stopRequested, "Stop already requested."); |
| stopRequested = true; |
| |
| foreach (var cq in completionQueues) |
| { |
| cq.Shutdown(); |
| } |
| } |
| |
| return Task.Run(() => |
| { |
| foreach (var thread in threads) |
| { |
| thread.Join(); |
| } |
| |
| foreach (var cq in completionQueues) |
| { |
| cq.Dispose(); |
| } |
| |
| for (int i = 0; i < threadProfilers.Count; i++) |
| { |
| threadProfilers[i].Dump(string.Format("grpc_trace_thread_{0}.txt", i)); |
| } |
| }); |
| } |
| |
| /// <summary> |
| /// Returns true if there is at least one thread pool thread that hasn't |
| /// already stopped. |
| /// Threads can either stop because all completion queues shut down or |
| /// because all foreground threads have already shutdown and process is |
| /// going to exit. |
| /// </summary> |
| internal bool IsAlive |
| { |
| get |
| { |
| return threads.Any(t => t.ThreadState != ThreadState.Stopped); |
| } |
| } |
| |
| internal IReadOnlyCollection<CompletionQueueSafeHandle> CompletionQueues |
| { |
| get |
| { |
| return completionQueues; |
| } |
| } |
| |
| private Thread CreateAndStartThread(int threadIndex, IProfiler optionalProfiler) |
| { |
| var cqIndex = threadIndex % completionQueues.Count; |
| var cq = completionQueues.ElementAt(cqIndex); |
| |
| var thread = new Thread(new ThreadStart(() => RunHandlerLoop(cq, optionalProfiler))); |
| thread.IsBackground = true; |
| thread.Name = string.Format("grpc {0} (cq {1})", threadIndex, cqIndex); |
| thread.Start(); |
| |
| return thread; |
| } |
| |
| /// <summary> |
| /// Body of the polling thread. |
| /// </summary> |
| private void RunHandlerLoop(CompletionQueueSafeHandle cq, IProfiler optionalProfiler) |
| { |
| if (optionalProfiler != null) |
| { |
| Profilers.SetForCurrentThread(optionalProfiler); |
| } |
| |
| CompletionQueueEvent ev; |
| do |
| { |
| ev = cq.Next(); |
| if (ev.type == CompletionQueueEvent.CompletionType.OpComplete) |
| { |
| bool success = (ev.success != 0); |
| IntPtr tag = ev.tag; |
| try |
| { |
| var callback = cq.CompletionRegistry.Extract(tag); |
| queuedContinuationCounter.Increment(); |
| if (!inlineHandlers) |
| { |
| // Use cached delegates to avoid unnecessary allocations |
| ThreadPool.QueueUserWorkItem(success ? runCompletionQueueEventCallbackSuccess : runCompletionQueueEventCallbackFailure, callback); |
| } |
| else |
| { |
| RunCompletionQueueEventCallback(callback, success); |
| } |
| } |
| catch (Exception e) |
| { |
| Logger.Error(e, "Exception occurred while extracting event from completion registry."); |
| } |
| } |
| } |
| while (ev.type != CompletionQueueEvent.CompletionType.Shutdown); |
| |
| // Continuations are running on default threadpool that consists of background threads. |
| // GrpcThreadPool thread (a foreground thread) will not exit unless all queued work had |
| // been finished to prevent terminating the continuations queued prematurely. |
| int sleepIterations = 0; |
| while (queuedContinuationCounter.Count != 0) |
| { |
| // Only happens on shutdown and having pending continuations shouldn't very common, |
| // so sleeping here for a little bit is fine. |
| if (sleepIterations >= MaxFinishContinuationsSleepTotalMillis / FinishContinuationsSleepMillis) |
| { |
| Logger.Warning("Shutting down gRPC thread [{0}] with unfinished callbacks (Timed out waiting for callbacks to finish).", |
| Thread.CurrentThread.Name); |
| break; |
| } |
| Thread.Sleep(FinishContinuationsSleepMillis); |
| sleepIterations ++; |
| } |
| } |
| |
| private static IReadOnlyCollection<CompletionQueueSafeHandle> CreateCompletionQueueList(GrpcEnvironment environment, int completionQueueCount) |
| { |
| var list = new List<CompletionQueueSafeHandle>(); |
| for (int i = 0; i < completionQueueCount; i++) |
| { |
| var completionRegistry = new CompletionRegistry(environment, () => environment.BatchContextPool.Lease(), () => environment.RequestCallContextPool.Lease()); |
| list.Add(CompletionQueueSafeHandle.CreateAsync(completionRegistry)); |
| } |
| return list.AsReadOnly(); |
| } |
| |
| private void RunCompletionQueueEventCallback(IOpCompletionCallback callback, bool success) |
| { |
| try |
| { |
| callback.OnComplete(success); |
| } |
| catch (Exception e) |
| { |
| Logger.Error(e, "Exception occurred while invoking completion delegate"); |
| } |
| finally |
| { |
| queuedContinuationCounter.Decrement(); |
| } |
| } |
| } |
| } |