threadpool.cc 2.4 KB
Newer Older
D
dzhwinter 已提交
1 2
/* Copyright (c) 2016 PaddlePaddle Authors. All Rights Reserve.

Y
Yi Wang 已提交
3 4 5
   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
D
dzhwinter 已提交
6

Y
Yi Wang 已提交
7
   http://www.apache.org/licenses/LICENSE-2.0
D
dzhwinter 已提交
8

Y
Yi Wang 已提交
9 10 11 12 13
   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. */
D
dzhwinter 已提交
14

Y
Yi Wang 已提交
15
#include "paddle/fluid/framework/threadpool.h"
D
dzhwinter 已提交
16

Y
Yi Wang 已提交
17
#include "paddle/fluid/platform/enforce.h"
Y
Yi Wang 已提交
18

D
dzhwinter 已提交
19 20 21
namespace paddle {
namespace framework {

Y
Yi Wang 已提交
22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92
std::unique_ptr<ThreadPool> ThreadPool::threadpool_(nullptr);
std::once_flag ThreadPool::init_flag_;

ThreadPool* ThreadPool::GetInstance() {
  std::call_once(init_flag_, &ThreadPool::Init);
  return threadpool_.get();
}

void ThreadPool::Init() {
  if (threadpool_.get() == nullptr) {
    // TODO(Yancey1989): specify the max threads number
    int num_threads = std::thread::hardware_concurrency();
    PADDLE_ENFORCE_GT(num_threads, 0);
    threadpool_.reset(new ThreadPool(num_threads));
  }
}

ThreadPool::ThreadPool(int num_threads)
    : total_threads_(num_threads), idle_threads_(num_threads), running_(true) {
  threads_.resize(num_threads);
  for (auto& thread : threads_) {
    // TODO(Yancey1989): binding the thread on the specify CPU number
    thread.reset(new std::thread(std::bind(&ThreadPool::TaskLoop, this)));
  }
}

ThreadPool::~ThreadPool() {
  {
    // notify all threads to stop running
    running_ = false;
    scheduled_.notify_all();
  }

  for (auto& t : threads_) {
    t->join();
    t.reset(nullptr);
  }
}

void ThreadPool::Wait() {
  std::unique_lock<std::mutex> lock(mutex_);
  completed_.wait(lock, [=] { return Done() == true; });
}

void ThreadPool::TaskLoop() {
  while (running_) {
    std::unique_lock<std::mutex> lock(mutex_);
    scheduled_.wait(lock, [=] { return !tasks_.empty() || !running_; });

    if (!running_) {
      break;
    }
    // pop a task from the task queue
    auto task = std::move(tasks_.front());
    tasks_.pop();

    --idle_threads_;
    lock.unlock();

    // run the task
    task();

    {
      std::unique_lock<std::mutex> lock(mutex_);
      ++idle_threads_;
      if (Done()) {
        completed_.notify_all();
      }
    }
  }
}
D
dzhwinter 已提交
93 94 95

}  // namespace framework
}  // namespace paddle