| // Copyright (c) 2011-present, Facebook, Inc. All rights reserved. |
| // This source code is licensed under both the GPLv2 (found in the |
| // COPYING file in the root directory) and Apache 2.0 License |
| // (found in the LICENSE.Apache file in the root directory). |
| // |
| // Copyright (c) 2011 The LevelDB Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. See the AUTHORS file for names of contributors. |
| #pragma once |
| |
| #include <functional> |
| |
| namespace rocksdb { |
| |
| /* |
| * ThreadPool is a component that will spawn N background threads that will |
| * be used to execute scheduled work, The number of background threads could |
| * be modified by calling SetBackgroundThreads(). |
| * */ |
| class ThreadPool { |
| public: |
| virtual ~ThreadPool() {} |
| |
| // Wait for all threads to finish. |
| // Discard those threads that did not start |
| // executing |
| virtual void JoinAllThreads() = 0; |
| |
| // Set the number of background threads that will be executing the |
| // scheduled jobs. |
| virtual void SetBackgroundThreads(int num) = 0; |
| virtual int GetBackgroundThreads() = 0; |
| |
| // Get the number of jobs scheduled in the ThreadPool queue. |
| virtual unsigned int GetQueueLen() const = 0; |
| |
| // Waits for all jobs to complete those |
| // that already started running and those that did not |
| // start yet. This ensures that everything that was thrown |
| // on the TP runs even though |
| // we may not have specified enough threads for the amount |
| // of jobs |
| virtual void WaitForJobsAndJoinAllThreads() = 0; |
| |
| // Submit a fire and forget jobs |
| // This allows to submit the same job multiple times |
| virtual void SubmitJob(const std::function<void()>&) = 0; |
| // This moves the function in for efficiency |
| virtual void SubmitJob(std::function<void()>&&) = 0; |
| |
| }; |
| |
| // NewThreadPool() is a function that could be used to create a ThreadPool |
| // with `num_threads` background threads. |
| extern ThreadPool* NewThreadPool(int num_threads); |
| |
| } // namespace rocksdb |