158 lines
4.5 KiB
C++
158 lines
4.5 KiB
C++
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/* Filename: thread_pool.h
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* Copyright: Shanghai Baosight Software Co., Ltd.
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*
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* Description: thread pool for async tasks
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*
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* @author: wuzheqiang
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* @version: 09/10/2024 wuzheqiang Initial Version
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**************************************************************/
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#ifndef DRSDK_THREAD_POOL_H
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#define DRSDK_THREAD_POOL_H
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#include <atomic>
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#include <condition_variable>
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#include <functional>
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#include <future>
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#include <memory>
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#include <mutex>
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#include <queue>
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#include <stdexcept>
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#include <thread>
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#include <vector>
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namespace dsfapi
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{
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class ThreadPool
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{
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public:
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/**
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* @brief the constructor just launches some amount of workers
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* @param [in] nThreads threads number
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* @version 09/10/2024 wuzheqiang Initial Version
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*/
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ThreadPool(uint32_t nThreads);
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/**
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* @brief the destructor joins all threads
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* @version 09/10/2024 wuzheqiang Initial Version
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*/
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~ThreadPool();
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/**
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* @brief add new work item to the pool
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* @param [in] assign assign the thread
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* @param [in] f function to be executed
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* @param [in] args function arguments
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* @return futurn if success
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* @version 09/10/2024 wuzheqiang Initial Version
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*/
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template <class F, class... Args>
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auto Enqueue(const int assign, F &&f, Args &&...args) -> std::future<typename std::result_of<F(Args...)>::type>;
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bool IsFull(const int assign)
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{
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static uint32_t MAX_SIZE = 100;
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std::unique_lock<std::mutex> lock(m_QueueMutex[assign % m_nThreads]);
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return m_QueTasks[assign % m_nThreads].size() >= MAX_SIZE;
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}
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private:
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// need to keep track of threads so we can join them
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uint32_t m_nThreads = 0;
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std::vector<std::thread> m_vecWorkers;
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// the task queue
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std::unique_ptr<std::queue<std::function<void()>>[]> m_QueTasks;
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// synchronization
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std::unique_ptr<std::mutex[]> m_QueueMutex;
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std::unique_ptr<std::condition_variable[]> m_QueueCv;
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std::atomic_bool m_bStop = {false};
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};
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inline ThreadPool::ThreadPool(uint32_t nThreads) : m_nThreads(nThreads)
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{
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// m_nThreads = nThreads;
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if (m_nThreads <= 0 || m_nThreads > 16)
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{
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m_nThreads = 16;
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}
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m_bStop.store(false);
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m_QueTasks =
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std::unique_ptr<std::queue<std::function<void()>>[]>(new std::queue<std::function<void()>>[m_nThreads]);
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m_QueueMutex = std::unique_ptr<std::mutex[]>(new std::mutex[m_nThreads]);
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m_QueueCv = std::unique_ptr<std::condition_variable[]>(new std::condition_variable[m_nThreads]);
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for (uint32_t i = 0; i < m_nThreads; ++i)
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{
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std::thread td([this, i] {
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while (!m_bStop)
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{
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std::function<void()> task;
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{
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std::unique_lock<std::mutex> lock(this->m_QueueMutex[i]);
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this->m_QueueCv[i].wait(lock, [this, i] { return this->m_bStop || !this->m_QueTasks[i].empty(); });
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if (this->m_bStop && this->m_QueTasks[i].empty())
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return;
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task = std::move(this->m_QueTasks[i].front());
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this->m_QueTasks[i].pop();
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}
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try
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{
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task();
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}
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catch (...)
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{
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}
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}
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});
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std::string name = "pool_" + std::to_string(i);
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pthread_setname_np(td.native_handle(), name.c_str());
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m_vecWorkers.emplace_back(std::move(td));
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}
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}
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inline ThreadPool::~ThreadPool()
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{
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if (m_bStop.exchange(true))
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{
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return;
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}
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for (int i = 0; i < m_nThreads; ++i)
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{
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m_QueueCv[i].notify_all();
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}
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for (std::thread &worker : m_vecWorkers)
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{
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worker.join();
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}
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}
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template <class F, class... Args>
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auto ThreadPool::Enqueue(const int assign, F &&f, Args &&...args)
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-> std::future<typename std::result_of<F(Args...)>::type>
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{
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using return_type = typename std::result_of<F(Args...)>::type;
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auto task =
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std::make_shared<std::packaged_task<return_type()>>(std::bind(std::forward<F>(f), std::forward<Args>(args)...));
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auto work_id = assign % m_nThreads;
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std::future<return_type> res = task->get_future();
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{
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std::unique_lock<std::mutex> lock(m_QueueMutex[work_id]);
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// don't allow enqueueing after stopping the pool
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if (m_bStop)
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return std::future<return_type>();
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m_QueTasks[work_id].emplace([task]() { (*task)(); });
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}
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m_QueueCv[work_id].notify_one();
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return res;
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}
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} // namespace dsfapi
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#endif |