TaskPool.h

Go to the documentation of this file.

/*
Copyright (c) 2018 DIVIDE-Studio
Copyright (c) 2009 Ionut Cava
 
This file is part of DIVIDE Framework.
 
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software
and associated documentation files (the "Software"), to deal in the Software
without restriction,
including without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the
Software is furnished to do so,
subject to the following conditions:
 
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
 
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED,
INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
IN CONNECTION WITH THE SOFTWARE
OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
*/
 
#pragma once
#ifndef DVD_TASK_POOL_H_
#define DVD_TASK_POOL_H_
 
#include "Platform/Threading/Headers/Task.h"
 
namespace Divide {
 
struct ParallelForDescriptor
{
    U32 _iterCount = 0u;
    U32 _partitionSize = 0u;
    TaskPriority _priority = TaskPriority::DONT_CARE;
    bool _waitForFinish = true;
    bool _useCurrentThread = true;
    bool _allowPoolIdle = true;
    bool _allowRunInIdle = true;
};
 
using PoolTask = DELEGATE_STD<bool, bool/*threadWaitingCall*/>;
 
class TaskPool final : public GUIDWrapper {
public:
  public:
 
    constexpr static bool IsBlocking = true;
 
    explicit TaskPool(std::string_view workerName);
    ~TaskPool();
 
    bool init(size_t threadCount, const DELEGATE<void, const std::thread::id&>& onThreadCreate = {});
    void shutdown();
 
    static Task* AllocateTask(Task* parentTask, DELEGATE<void, Task&>&& func, bool allowedInIdle ) noexcept;
 
    size_t flushCallbackQueue();
    void waitForAllTasks(bool flushCallbacks);
 
    void threadWaiting();
 
 
    // Add a new task to the pool's queue
    bool addTask( PoolTask&& job );
 
    // Reinitializes the thread pool (joins and closes out all existing threads first)
    void init();
    // Join all of the threads and block until all running tasks have completed.
    void join();
 
    // Wait for all running jobs to finish
    void wait() const noexcept;
 
    void executeOneTask( bool isIdleCall );
 
    PROPERTY_R( vector<std::thread>, threads );
 
 
  private:
    //ToDo: replace all friend class declarations with attorneys -Ionut;
    friend struct Task;
    friend void Start(Task& task, TaskPool& pool, const TaskPriority priority, const DELEGATE<void>& onCompletionFunction);
    friend void Wait(const Task& task, TaskPool& pool);
    friend void Parallel_For(TaskPool& pool, const ParallelForDescriptor& descriptor);
 
    void taskStarted(Task& task);
    void taskCompleted(Task& task);
    
    bool enqueue(Task& task, TaskPriority priority, const DELEGATE<void>& onCompletionFunction);
    bool runRealTime(Task& task, const DELEGATE<void>& onCompletionFunction );
 
    bool deque( bool isIdleCall, PoolTask& taskOut );
    void waitForTask(const Task& task);
 
  private:
     const string _threadNamePrefix;
 
     struct CallbackEntry
     {
         DELEGATE<void> _cbk;
         U32 _taskID = U32_MAX;
     };
 
     SharedMutex _taskCallbacksLock;
     eastl::fixed_vector<CallbackEntry, 1 << 9, true> _taskCallbacks;
 
     moodycamel::ConcurrentQueue<U32> _threadedCallbackBuffer{};
 
     using QueueType = std::conditional_t<IsBlocking, moodycamel::BlockingConcurrentQueue<PoolTask>, moodycamel::ConcurrentQueue<PoolTask>>;
     QueueType _queue;
 
     Mutex _taskFinishedMutex;
     std::condition_variable _taskFinishedCV;
     DELEGATE<void, const std::thread::id&> _threadCreateCbk{};
 
     std::atomic_uint _runningTaskCount = 0u;
     std::atomic_size_t _activeThreads{ 0u };
 
     bool _isRunning{ true };
};
 
template<class Predicate>
Task* CreateTask(Predicate&& threadedFunction, bool allowedInIdle = true);
 
template<class Predicate>
Task* CreateTask(Task* parentTask, Predicate&& threadedFunction, bool allowedInIdle = true);
 
void Parallel_For(TaskPool& pool, const ParallelForDescriptor& descriptor, const DELEGATE<void, const Task*, U32/*start*/, U32/*end*/>& cbk);
 
} //namespace Divide
 
#endif //DVD_TASK_POOL_H_
 
#include "TaskPool.inl"