Anthony Barbier | 6ff3b19 | 2017-09-04 18:44:23 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2016, 2017 ARM Limited. |
| 3 | * |
| 4 | * SPDX-License-Identifier: MIT |
| 5 | * |
| 6 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
| 7 | * of this software and associated documentation files (the "Software"), to |
| 8 | * deal in the Software without restriction, including without limitation the |
| 9 | * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or |
| 10 | * sell copies of the Software, and to permit persons to whom the Software is |
| 11 | * furnished to do so, subject to the following conditions: |
| 12 | * |
| 13 | * The above copyright notice and this permission notice shall be included in all |
| 14 | * copies or substantial portions of the Software. |
| 15 | * |
| 16 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| 17 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 18 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| 19 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| 20 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| 21 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
| 22 | * SOFTWARE. |
| 23 | */ |
| 24 | #include "arm_compute/runtime/CPP/CPPScheduler.h" |
| 25 | |
| 26 | #include "arm_compute/core/CPP/ICPPKernel.h" |
| 27 | #include "arm_compute/core/Error.h" |
| 28 | #include "arm_compute/core/Helpers.h" |
| 29 | #include "arm_compute/core/Utils.h" |
| 30 | |
| 31 | #include <iostream> |
| 32 | #include <semaphore.h> |
| 33 | #include <system_error> |
| 34 | #include <thread> |
| 35 | |
| 36 | using namespace arm_compute; |
| 37 | |
| 38 | class arm_compute::Thread |
| 39 | { |
| 40 | public: |
| 41 | /** Start a new thread |
| 42 | */ |
| 43 | Thread(); |
| 44 | Thread(const Thread &) = delete; |
| 45 | Thread &operator=(const Thread &) = delete; |
| 46 | Thread(Thread &&) = delete; |
| 47 | Thread &operator=(Thread &&) = delete; |
| 48 | /** Make the thread join |
| 49 | */ |
| 50 | ~Thread(); |
| 51 | /** Request the worker thread to start executing the given kernel |
| 52 | * This function will return as soon as the kernel has been sent to the worker thread. |
| 53 | * wait() needs to be called to ensure the execution is complete. |
| 54 | */ |
| 55 | void start(ICPPKernel *kernel, const Window &window); |
| 56 | /** Wait for the current kernel execution to complete |
| 57 | */ |
| 58 | void wait(); |
| 59 | /** Function ran by the worker thread |
| 60 | */ |
| 61 | void worker_thread(); |
| 62 | |
| 63 | private: |
| 64 | std::thread _thread; |
| 65 | ICPPKernel *_kernel{ nullptr }; |
| 66 | Window _window; |
| 67 | sem_t _wait_for_work; |
| 68 | sem_t _job_complete; |
| 69 | std::exception_ptr _current_exception; |
| 70 | }; |
| 71 | |
| 72 | Thread::Thread() |
| 73 | : _thread(), _window(), _wait_for_work(), _job_complete(), _current_exception(nullptr) |
| 74 | { |
| 75 | int ret = sem_init(&_wait_for_work, 0, 0); |
| 76 | ARM_COMPUTE_ERROR_ON(ret < 0); |
| 77 | ARM_COMPUTE_UNUSED(ret); |
| 78 | |
| 79 | ret = sem_init(&_job_complete, 0, 0); |
| 80 | ARM_COMPUTE_ERROR_ON(ret < 0); |
| 81 | ARM_COMPUTE_UNUSED(ret); |
| 82 | |
| 83 | _thread = std::thread(&Thread::worker_thread, this); |
| 84 | } |
| 85 | |
| 86 | Thread::~Thread() |
| 87 | { |
| 88 | ARM_COMPUTE_ERROR_ON(!_thread.joinable()); |
| 89 | |
| 90 | start(nullptr, Window()); |
| 91 | _thread.join(); |
| 92 | |
| 93 | int ret = sem_destroy(&_wait_for_work); |
| 94 | ARM_COMPUTE_ERROR_ON(ret < 0); |
| 95 | ARM_COMPUTE_UNUSED(ret); |
| 96 | |
| 97 | ret = sem_destroy(&_job_complete); |
| 98 | ARM_COMPUTE_ERROR_ON(ret < 0); |
| 99 | ARM_COMPUTE_UNUSED(ret); |
| 100 | } |
| 101 | |
| 102 | void Thread::start(ICPPKernel *kernel, const Window &window) |
| 103 | { |
| 104 | _kernel = kernel; |
| 105 | _window = window; |
| 106 | int ret = sem_post(&_wait_for_work); |
| 107 | ARM_COMPUTE_UNUSED(ret); |
| 108 | ARM_COMPUTE_ERROR_ON(ret < 0); |
| 109 | } |
| 110 | |
| 111 | void Thread::wait() |
| 112 | { |
| 113 | int ret = sem_wait(&_job_complete); |
| 114 | ARM_COMPUTE_UNUSED(ret); |
| 115 | ARM_COMPUTE_ERROR_ON(ret < 0); |
| 116 | if(_current_exception) |
| 117 | { |
| 118 | std::rethrow_exception(_current_exception); |
| 119 | } |
| 120 | } |
| 121 | |
| 122 | void Thread::worker_thread() |
| 123 | { |
| 124 | while(sem_wait(&_wait_for_work) >= 0) |
| 125 | { |
| 126 | _current_exception = nullptr; |
| 127 | // Time to exit |
| 128 | if(_kernel == nullptr) |
| 129 | { |
| 130 | return; |
| 131 | } |
| 132 | |
| 133 | try |
| 134 | { |
| 135 | _window.validate(); |
| 136 | _kernel->run(_window); |
| 137 | } |
| 138 | catch(...) |
| 139 | { |
| 140 | _current_exception = std::current_exception(); |
| 141 | } |
| 142 | int ret = sem_post(&_job_complete); |
| 143 | ARM_COMPUTE_UNUSED(ret); |
| 144 | ARM_COMPUTE_ERROR_ON(ret < 0); |
| 145 | } |
| 146 | |
| 147 | ARM_COMPUTE_ERROR("Wait failed"); |
| 148 | } |
| 149 | |
| 150 | namespace |
| 151 | { |
| 152 | void delete_threads(Thread *t) |
| 153 | { |
| 154 | delete[] t; |
| 155 | } |
| 156 | } // namespace |
| 157 | |
| 158 | CPPScheduler &CPPScheduler::get() |
| 159 | { |
| 160 | static CPPScheduler scheduler; |
| 161 | return scheduler; |
| 162 | } |
| 163 | |
| 164 | unsigned int CPPScheduler::num_threads() const |
| 165 | { |
| 166 | return _num_threads; |
| 167 | } |
| 168 | |
| 169 | CPPScheduler::CPPScheduler() |
| 170 | : _num_threads(std::thread::hardware_concurrency()), |
| 171 | _threads(std::unique_ptr<Thread[], void(*)(Thread *)>(new Thread[std::thread::hardware_concurrency() - 1], delete_threads)) |
| 172 | { |
| 173 | } |
| 174 | |
| 175 | void CPPScheduler::set_num_threads(unsigned int num_threads) |
| 176 | { |
| 177 | const unsigned int num_cores = std::thread::hardware_concurrency(); |
| 178 | _num_threads = num_threads == 0 ? num_cores : num_threads; |
| 179 | } |
| 180 | |
| 181 | void CPPScheduler::schedule(ICPPKernel *kernel, unsigned int split_dimension) |
| 182 | { |
| 183 | ARM_COMPUTE_ERROR_ON_MSG(!kernel, "The child class didn't set the kernel"); |
| 184 | |
| 185 | /** [Scheduler example] */ |
| 186 | const Window &max_window = kernel->window(); |
| 187 | const unsigned int num_iterations = max_window.num_iterations(split_dimension); |
| 188 | const unsigned int num_threads = std::min(num_iterations, _num_threads); |
| 189 | |
| 190 | if(!kernel->is_parallelisable() || 1 == num_threads) |
| 191 | { |
| 192 | kernel->run(max_window); |
| 193 | } |
| 194 | else |
| 195 | { |
| 196 | for(unsigned int t = 0; t < num_threads; ++t) |
| 197 | { |
| 198 | Window win = max_window.split_window(split_dimension, t, num_threads); |
| 199 | win.set_thread_id(t); |
| 200 | win.set_num_threads(num_threads); |
| 201 | |
| 202 | if(t != num_threads - 1) |
| 203 | { |
| 204 | _threads[t].start(kernel, win); |
| 205 | } |
| 206 | else |
| 207 | { |
| 208 | kernel->run(win); |
| 209 | } |
| 210 | } |
| 211 | |
| 212 | try |
| 213 | { |
| 214 | for(unsigned int t = 1; t < num_threads; ++t) |
| 215 | { |
| 216 | _threads[t - 1].wait(); |
| 217 | } |
| 218 | } |
| 219 | catch(const std::system_error &e) |
| 220 | { |
| 221 | std::cout << "Caught system_error with code " << e.code() << " meaning " << e.what() << '\n'; |
| 222 | } |
| 223 | } |
| 224 | /** [Scheduler example] */ |
| 225 | } |