1 /* 2 * Copyright (C) 2012 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef ART_RUNTIME_THREAD_POOL_H_ 18 #define ART_RUNTIME_THREAD_POOL_H_ 19 20 #include <deque> 21 #include <vector> 22 23 #include "barrier.h" 24 #include "base/mutex.h" 25 #include "mem_map.h" 26 27 namespace art { 28 29 class ThreadPool; 30 31 class Closure { 32 public: 33 virtual ~Closure() { } 34 virtual void Run(Thread* self) = 0; 35 }; 36 37 class Task : public Closure { 38 public: 39 // Called after Closure::Run has been called. 40 virtual void Finalize() { } 41 }; 42 43 class SelfDeletingTask : public Task { 44 public: 45 virtual ~SelfDeletingTask() { } 46 virtual void Finalize() { 47 delete this; 48 } 49 }; 50 51 class ThreadPoolWorker { 52 public: 53 static const size_t kDefaultStackSize = 1 * MB; 54 55 size_t GetStackSize() const { 56 DCHECK(stack_.get() != nullptr); 57 return stack_->Size(); 58 } 59 60 virtual ~ThreadPoolWorker(); 61 62 // Set the "nice" priorty for this worker. 63 void SetPthreadPriority(int priority); 64 65 Thread* GetThread() const { return thread_; } 66 67 protected: 68 ThreadPoolWorker(ThreadPool* thread_pool, const std::string& name, size_t stack_size); 69 static void* Callback(void* arg) REQUIRES(!Locks::mutator_lock_); 70 virtual void Run(); 71 72 ThreadPool* const thread_pool_; 73 const std::string name_; 74 std::unique_ptr<MemMap> stack_; 75 pthread_t pthread_; 76 Thread* thread_; 77 78 private: 79 friend class ThreadPool; 80 DISALLOW_COPY_AND_ASSIGN(ThreadPoolWorker); 81 }; 82 83 // Note that thread pool workers will set Thread#setCanCallIntoJava to false. 84 class ThreadPool { 85 public: 86 // Returns the number of threads in the thread pool. 87 size_t GetThreadCount() const { 88 return threads_.size(); 89 } 90 91 const std::vector<ThreadPoolWorker*>& GetWorkers() const { 92 return threads_; 93 } 94 95 // Broadcast to the workers and tell them to empty out the work queue. 96 void StartWorkers(Thread* self) REQUIRES(!task_queue_lock_); 97 98 // Do not allow workers to grab any new tasks. 99 void StopWorkers(Thread* self) REQUIRES(!task_queue_lock_); 100 101 // Add a new task, the first available started worker will process it. Does not delete the task 102 // after running it, it is the caller's responsibility. 103 void AddTask(Thread* self, Task* task) REQUIRES(!task_queue_lock_); 104 105 // Remove all tasks in the queue. 106 void RemoveAllTasks(Thread* self) REQUIRES(!task_queue_lock_); 107 108 // Create a named thread pool with the given number of threads. 109 // 110 // If create_peers is true, all worker threads will have a Java peer object. Note that if the 111 // pool is asked to do work on the current thread (see Wait), a peer may not be available. Wait 112 // will conservatively abort if create_peers and do_work are true. 113 ThreadPool(const char* name, size_t num_threads, bool create_peers = false); 114 virtual ~ThreadPool(); 115 116 // Wait for all tasks currently on queue to get completed. If the pool has been stopped, only 117 // wait till all already running tasks are done. 118 // When the pool was created with peers for workers, do_work must not be true (see ThreadPool()). 119 void Wait(Thread* self, bool do_work, bool may_hold_locks) REQUIRES(!task_queue_lock_); 120 121 size_t GetTaskCount(Thread* self) REQUIRES(!task_queue_lock_); 122 123 // Returns the total amount of workers waited for tasks. 124 uint64_t GetWaitTime() const { 125 return total_wait_time_; 126 } 127 128 // Provides a way to bound the maximum number of worker threads, threads must be less the the 129 // thread count of the thread pool. 130 void SetMaxActiveWorkers(size_t threads) REQUIRES(!task_queue_lock_); 131 132 // Set the "nice" priorty for threads in the pool. 133 void SetPthreadPriority(int priority); 134 135 protected: 136 // get a task to run, blocks if there are no tasks left 137 virtual Task* GetTask(Thread* self) REQUIRES(!task_queue_lock_); 138 139 // Try to get a task, returning null if there is none available. 140 Task* TryGetTask(Thread* self) REQUIRES(!task_queue_lock_); 141 Task* TryGetTaskLocked() REQUIRES(task_queue_lock_); 142 143 // Are we shutting down? 144 bool IsShuttingDown() const REQUIRES(task_queue_lock_) { 145 return shutting_down_; 146 } 147 148 bool HasOutstandingTasks() const REQUIRES(task_queue_lock_) { 149 return started_ && !tasks_.empty(); 150 } 151 152 const std::string name_; 153 Mutex task_queue_lock_; 154 ConditionVariable task_queue_condition_ GUARDED_BY(task_queue_lock_); 155 ConditionVariable completion_condition_ GUARDED_BY(task_queue_lock_); 156 volatile bool started_ GUARDED_BY(task_queue_lock_); 157 volatile bool shutting_down_ GUARDED_BY(task_queue_lock_); 158 // How many worker threads are waiting on the condition. 159 volatile size_t waiting_count_ GUARDED_BY(task_queue_lock_); 160 std::deque<Task*> tasks_ GUARDED_BY(task_queue_lock_); 161 // TODO: make this immutable/const? 162 std::vector<ThreadPoolWorker*> threads_; 163 // Work balance detection. 164 uint64_t start_time_ GUARDED_BY(task_queue_lock_); 165 uint64_t total_wait_time_; 166 Barrier creation_barier_; 167 size_t max_active_workers_ GUARDED_BY(task_queue_lock_); 168 const bool create_peers_; 169 170 private: 171 friend class ThreadPoolWorker; 172 friend class WorkStealingWorker; 173 DISALLOW_COPY_AND_ASSIGN(ThreadPool); 174 }; 175 176 } // namespace art 177 178 #endif // ART_RUNTIME_THREAD_POOL_H_ 179
