folly/executors/CPUThreadPoolExecutor.cpp

   1 /*
   2  * Copyright 2017-present Facebook, Inc.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *   http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include <folly/executors/CPUThreadPoolExecutor.h>
  18 #include <folly/executors/task_queue/PriorityLifoSemMPMCQueue.h>
  19
  20 namespace folly {
  21
  22 const size_t CPUThreadPoolExecutor::kDefaultMaxQueueSize = 1 << 14;
  23
  24 CPUThreadPoolExecutor::CPUThreadPoolExecutor(
  25     size_t numThreads,
  26     std::unique_ptr<BlockingQueue<CPUTask>> taskQueue,
  27     std::shared_ptr<ThreadFactory> threadFactory)
  28     : ThreadPoolExecutor(numThreads, std::move(threadFactory)),
  29       taskQueue_(std::move(taskQueue)) {
  30   setNumThreads(numThreads);
  31 }
  32
  33 CPUThreadPoolExecutor::CPUThreadPoolExecutor(
  34     size_t numThreads,
  35     std::shared_ptr<ThreadFactory> threadFactory)
  36     : CPUThreadPoolExecutor(
  37           numThreads,
  38           std::make_unique<LifoSemMPMCQueue<CPUTask>>(
  39               CPUThreadPoolExecutor::kDefaultMaxQueueSize),
  40           std::move(threadFactory)) {}
  41
  42 CPUThreadPoolExecutor::CPUThreadPoolExecutor(size_t numThreads)
  43     : CPUThreadPoolExecutor(
  44           numThreads,
  45           std::make_shared<NamedThreadFactory>("CPUThreadPool")) {}
  46
  47 CPUThreadPoolExecutor::CPUThreadPoolExecutor(
  48     size_t numThreads,
  49     int8_t numPriorities,
  50     std::shared_ptr<ThreadFactory> threadFactory)
  51     : CPUThreadPoolExecutor(
  52           numThreads,
  53           std::make_unique<PriorityLifoSemMPMCQueue<CPUTask>>(
  54               numPriorities,
  55               CPUThreadPoolExecutor::kDefaultMaxQueueSize),
  56           std::move(threadFactory)) {}
  57
  58 CPUThreadPoolExecutor::CPUThreadPoolExecutor(
  59     size_t numThreads,
  60     int8_t numPriorities,
  61     size_t maxQueueSize,
  62     std::shared_ptr<ThreadFactory> threadFactory)
  63     : CPUThreadPoolExecutor(
  64           numThreads,
  65           std::make_unique<PriorityLifoSemMPMCQueue<CPUTask>>(
  66               numPriorities,
  67               maxQueueSize),
  68           std::move(threadFactory)) {}
  69
  70 CPUThreadPoolExecutor::~CPUThreadPoolExecutor() {
  71   stop();
  72   CHECK(threadsToStop_ == 0);
  73 }
  74
  75 void CPUThreadPoolExecutor::add(Func func) {
  76   add(std::move(func), std::chrono::milliseconds(0));
  77 }
  78
  79 void CPUThreadPoolExecutor::add(
  80     Func func,
  81     std::chrono::milliseconds expiration,
  82     Func expireCallback) {
  83   // TODO handle enqueue failure, here and in other add() callsites
  84   taskQueue_->add(
  85       CPUTask(std::move(func), expiration, std::move(expireCallback)));
  86 }
  87
  88 void CPUThreadPoolExecutor::addWithPriority(Func func, int8_t priority) {
  89   add(std::move(func), priority, std::chrono::milliseconds(0));
  90 }
  91
  92 void CPUThreadPoolExecutor::add(
  93     Func func,
  94     int8_t priority,
  95     std::chrono::milliseconds expiration,
  96     Func expireCallback) {
  97   CHECK(getNumPriorities() > 0);
  98   taskQueue_->addWithPriority(
  99       CPUTask(std::move(func), expiration, std::move(expireCallback)),
 100       priority);
 101 }
 102
 103 uint8_t CPUThreadPoolExecutor::getNumPriorities() const {
 104   return taskQueue_->getNumPriorities();
 105 }
 106
 107 BlockingQueue<CPUThreadPoolExecutor::CPUTask>*
 108 CPUThreadPoolExecutor::getTaskQueue() {
 109   return taskQueue_.get();
 110 }
 111
 112 void CPUThreadPoolExecutor::threadRun(std::shared_ptr<Thread> thread) {
 113   this->threadPoolHook_.registerThread();
 114
 115   thread->startupBaton.post();
 116   while (true) {
 117     auto task = taskQueue_->take();
 118     if (UNLIKELY(task.poison)) {
 119       CHECK(threadsToStop_-- > 0);
 120       for (auto& o : observers_) {
 121         o->threadStopped(thread.get());
 122       }
 123       folly::RWSpinLock::WriteHolder w{&threadListLock_};
 124       threadList_.remove(thread);
 125       stoppedThreads_.add(thread);
 126       return;
 127     } else {
 128       runTask(thread, std::move(task));
 129     }
 130
 131     if (UNLIKELY(threadsToStop_ > 0 && !isJoin_)) {
 132       if (--threadsToStop_ >= 0) {
 133         folly::RWSpinLock::WriteHolder w{&threadListLock_};
 134         threadList_.remove(thread);
 135         stoppedThreads_.add(thread);
 136         return;
 137       } else {
 138         threadsToStop_++;
 139       }
 140     }
 141   }
 142 }
 143
 144 void CPUThreadPoolExecutor::stopThreads(size_t n) {
 145   threadsToStop_ += n;
 146   for (size_t i = 0; i < n; i++) {
 147     taskQueue_->addWithPriority(CPUTask(), Executor::LO_PRI);
 148   }
 149 }
 150
 151 // threadListLock_ is readlocked
 152 uint64_t CPUThreadPoolExecutor::getPendingTaskCountImpl(
 153     const folly::RWSpinLock::ReadHolder&) {
 154   return taskQueue_->size();
 155 }
 156
 157 } // namespace folly