1/* Copyright 2019 The TensorFlow Authors. All Rights Reserved.
2
3Licensed under the Apache License, Version 2.0 (the "License");
4you may not use this file except in compliance with the License.
5You may obtain a copy of the License at
6
7 http://www.apache.org/licenses/LICENSE-2.0
8
9Unless required by applicable law or agreed to in writing, software
10distributed under the License is distributed on an "AS IS" BASIS,
11WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12See the License for the specific language governing permissions and
13limitations under the License.
14==============================================================================*/
15#ifndef TENSORFLOW_CORE_DATA_UNBOUNDED_THREAD_POOL_H_
16#define TENSORFLOW_CORE_DATA_UNBOUNDED_THREAD_POOL_H_
17
18#include <deque>
19#include <memory>
20#include <vector>
21
22#include "tensorflow/core/framework/thread_factory.h"
23#include "tensorflow/core/lib/core/notification.h"
24#include "tensorflow/core/lib/core/threadpool_interface.h"
25#include "tensorflow/core/platform/env.h"
26#include "tensorflow/core/platform/unbounded_work_queue.h"
27
28namespace tensorflow {
29namespace data {
30
31// An `UnboundedThreadPool` provides a mechanism for temporally multiplexing a
32// potentially large number of "logical" threads onto a smaller number of
33// "physical" threads. The multiplexing is achieved by using an
34// `UnboundedWorkQueue`.
35class UnboundedThreadPool : public thread::ThreadPoolInterface {
36 public:
37 UnboundedThreadPool(Env* env, const string& thread_name)
38 : unbounded_work_queue_(env, thread_name) {}
39 UnboundedThreadPool(Env* env, const string& thread_name,
40 const ThreadOptions& thread_options)
41 : unbounded_work_queue_(env, thread_name, thread_options) {}
42 ~UnboundedThreadPool() override = default;
43
44 // Returns an implementation of `ThreadFactory` that can be used to create
45 // logical threads in this pool.
46 std::shared_ptr<ThreadFactory> get_thread_factory();
47
48 void Schedule(std::function<void()> fn) override;
49 int NumThreads() const override;
50 int CurrentThreadId() const override;
51
52 private:
53 class LogicalThreadFactory;
54 class LogicalThreadWrapper;
55
56 void ScheduleOnWorkQueue(std::function<void()> fn,
57 std::shared_ptr<Notification> done);
58
59 UnboundedWorkQueue unbounded_work_queue_;
60};
61
62} // namespace data
63} // namespace tensorflow
64
65#endif // TENSORFLOW_CORE_DATA_UNBOUNDED_THREAD_POOL_H_
66