diff options
Diffstat (limited to 'thirdparty/embree/common/tasking/taskschedulerinternal.cpp')
| -rw-r--r-- | thirdparty/embree/common/tasking/taskschedulerinternal.cpp | 420 |
1 files changed, 420 insertions, 0 deletions
diff --git a/thirdparty/embree/common/tasking/taskschedulerinternal.cpp b/thirdparty/embree/common/tasking/taskschedulerinternal.cpp new file mode 100644 index 0000000000..ad438588a3 --- /dev/null +++ b/thirdparty/embree/common/tasking/taskschedulerinternal.cpp @@ -0,0 +1,420 @@ +// Copyright 2009-2021 Intel Corporation +// SPDX-License-Identifier: Apache-2.0 + +#include "taskschedulerinternal.h" +#include "../math/math.h" +#include "../sys/sysinfo.h" +#include <algorithm> + +namespace embree +{ + RTC_NAMESPACE_BEGIN + + static MutexSys g_mutex; + size_t TaskScheduler::g_numThreads = 0; + __thread TaskScheduler* TaskScheduler::g_instance = nullptr; + std::vector<Ref<TaskScheduler>> g_instance_vector; + __thread TaskScheduler::Thread* TaskScheduler::thread_local_thread = nullptr; + TaskScheduler::ThreadPool* TaskScheduler::threadPool = nullptr; + + template<typename Predicate, typename Body> + __forceinline void TaskScheduler::steal_loop(Thread& thread, const Predicate& pred, const Body& body) + { + while (true) + { + /*! some rounds that yield */ + for (size_t i=0; i<32; i++) + { + /*! some spinning rounds */ + const size_t threadCount = thread.threadCount(); + for (size_t j=0; j<1024; j+=threadCount) + { + if (!pred()) return; + if (thread.scheduler->steal_from_other_threads(thread)) { + i=j=0; + body(); + } + } + yield(); + } + } + } + + /*! run this task */ + void TaskScheduler::Task::run_internal (Thread& thread) // FIXME: avoid as many dll_exports as possible + { + /* try to run if not already stolen */ + if (try_switch_state(INITIALIZED,DONE)) + { + Task* prevTask = thread.task; + thread.task = this; + // -- GODOT start -- + // try { + // if (thread.scheduler->cancellingException == nullptr) + closure->execute(); + // } catch (...) { + // if (thread.scheduler->cancellingException == nullptr) + // thread.scheduler->cancellingException = std::current_exception(); + // } + // -- GODOT end -- + thread.task = prevTask; + add_dependencies(-1); + } + + /* steal until all dependencies have completed */ + steal_loop(thread, + [&] () { return dependencies>0; }, + [&] () { while (thread.tasks.execute_local_internal(thread,this)); }); + + /* now signal our parent task that we are finished */ + if (parent) + parent->add_dependencies(-1); + } + + /*! run this task */ + dll_export void TaskScheduler::Task::run (Thread& thread) { + run_internal(thread); + } + + bool TaskScheduler::TaskQueue::execute_local_internal(Thread& thread, Task* parent) + { + /* stop if we run out of local tasks or reach the waiting task */ + if (right == 0 || &tasks[right-1] == parent) + return false; + + /* execute task */ + size_t oldRight = right; + tasks[right-1].run_internal(thread); + if (right != oldRight) { + THROW_RUNTIME_ERROR("you have to wait for spawned subtasks"); + } + + /* pop task and closure from stack */ + right--; + if (tasks[right].stackPtr != size_t(-1)) + stackPtr = tasks[right].stackPtr; + + /* also move left pointer */ + if (left >= right) left.store(right.load()); + + return right != 0; + } + + dll_export bool TaskScheduler::TaskQueue::execute_local(Thread& thread, Task* parent) { + return execute_local_internal(thread,parent); + } + + bool TaskScheduler::TaskQueue::steal(Thread& thread) + { + size_t l = left; + size_t r = right; + if (l < r) + { + l = left++; + if (l >= r) + return false; + } + else + return false; + + if (!tasks[l].try_steal(thread.tasks.tasks[thread.tasks.right])) + return false; + + thread.tasks.right++; + return true; + } + + /* we steal from the left */ + size_t TaskScheduler::TaskQueue::getTaskSizeAtLeft() + { + if (left >= right) return 0; + return tasks[left].N; + } + + void threadPoolFunction(std::pair<TaskScheduler::ThreadPool*,size_t>* pair) + { + TaskScheduler::ThreadPool* pool = pair->first; + size_t threadIndex = pair->second; + delete pair; + pool->thread_loop(threadIndex); + } + + TaskScheduler::ThreadPool::ThreadPool(bool set_affinity) + : numThreads(0), numThreadsRunning(0), set_affinity(set_affinity), running(false) {} + + dll_export void TaskScheduler::ThreadPool::startThreads() + { + if (running) return; + setNumThreads(numThreads,true); + } + + void TaskScheduler::ThreadPool::setNumThreads(size_t newNumThreads, bool startThreads) + { + Lock<MutexSys> lock(g_mutex); + assert(newNumThreads); + newNumThreads = min(newNumThreads, (size_t) getNumberOfLogicalThreads()); + + numThreads = newNumThreads; + if (!startThreads && !running) return; + running = true; + size_t numThreadsActive = numThreadsRunning; + + mutex.lock(); + numThreadsRunning = newNumThreads; + mutex.unlock(); + condition.notify_all(); + + /* start new threads */ + for (size_t t=numThreadsActive; t<numThreads; t++) + { + if (t == 0) continue; + auto pair = new std::pair<TaskScheduler::ThreadPool*,size_t>(this,t); + threads.push_back(createThread((thread_func)threadPoolFunction,pair,4*1024*1024,set_affinity ? t : -1)); + } + + /* stop some threads if we reduce the number of threads */ + for (ssize_t t=numThreadsActive-1; t>=ssize_t(numThreadsRunning); t--) { + if (t == 0) continue; + embree::join(threads.back()); + threads.pop_back(); + } + } + + TaskScheduler::ThreadPool::~ThreadPool() + { + /* leave all taskschedulers */ + mutex.lock(); + numThreadsRunning = 0; + mutex.unlock(); + condition.notify_all(); + + /* wait for threads to terminate */ + for (size_t i=0; i<threads.size(); i++) + embree::join(threads[i]); + } + + dll_export void TaskScheduler::ThreadPool::add(const Ref<TaskScheduler>& scheduler) + { + mutex.lock(); + schedulers.push_back(scheduler); + mutex.unlock(); + condition.notify_all(); + } + + dll_export void TaskScheduler::ThreadPool::remove(const Ref<TaskScheduler>& scheduler) + { + Lock<MutexSys> lock(mutex); + for (std::list<Ref<TaskScheduler> >::iterator it = schedulers.begin(); it != schedulers.end(); it++) { + if (scheduler == *it) { + schedulers.erase(it); + return; + } + } + } + + void TaskScheduler::ThreadPool::thread_loop(size_t globalThreadIndex) + { + while (globalThreadIndex < numThreadsRunning) + { + Ref<TaskScheduler> scheduler = NULL; + ssize_t threadIndex = -1; + { + Lock<MutexSys> lock(mutex); + condition.wait(mutex, [&] () { return globalThreadIndex >= numThreadsRunning || !schedulers.empty(); }); + if (globalThreadIndex >= numThreadsRunning) break; + scheduler = schedulers.front(); + threadIndex = scheduler->allocThreadIndex(); + } + scheduler->thread_loop(threadIndex); + } + } + + TaskScheduler::TaskScheduler() + : threadCounter(0), anyTasksRunning(0), hasRootTask(false) + { + threadLocal.resize(2*getNumberOfLogicalThreads()); // FIXME: this has to be 2x as in the compatibility join mode with rtcCommitScene the worker threads also join. When disallowing rtcCommitScene to join a build we can remove the 2x. + for (size_t i=0; i<threadLocal.size(); i++) + threadLocal[i].store(nullptr); + } + + TaskScheduler::~TaskScheduler() + { + assert(threadCounter == 0); + } + + dll_export size_t TaskScheduler::threadID() + { + Thread* thread = TaskScheduler::thread(); + if (thread) return thread->threadIndex; + else return 0; + } + + dll_export size_t TaskScheduler::threadIndex() + { + Thread* thread = TaskScheduler::thread(); + if (thread) return thread->threadIndex; + else return 0; + } + + dll_export size_t TaskScheduler::threadCount() { + return threadPool->size(); + } + + dll_export TaskScheduler* TaskScheduler::instance() + { + if (g_instance == NULL) { + Lock<MutexSys> lock(g_mutex); + g_instance = new TaskScheduler; + g_instance_vector.push_back(g_instance); + } + return g_instance; + } + + void TaskScheduler::create(size_t numThreads, bool set_affinity, bool start_threads) + { + if (!threadPool) threadPool = new TaskScheduler::ThreadPool(set_affinity); + threadPool->setNumThreads(numThreads,start_threads); + } + + void TaskScheduler::destroy() { + delete threadPool; threadPool = nullptr; + } + + dll_export ssize_t TaskScheduler::allocThreadIndex() + { + size_t threadIndex = threadCounter++; + assert(threadIndex < threadLocal.size()); + return threadIndex; + } + + void TaskScheduler::join() + { + mutex.lock(); + size_t threadIndex = allocThreadIndex(); + condition.wait(mutex, [&] () { return hasRootTask.load(); }); + mutex.unlock(); + // -- GODOT start -- + // std::exception_ptr except = thread_loop(threadIndex); + // if (except != nullptr) std::rethrow_exception(except); + thread_loop(threadIndex); + // -- GODOT end -- + } + + void TaskScheduler::reset() { + hasRootTask = false; + } + + void TaskScheduler::wait_for_threads(size_t threadCount) + { + while (threadCounter < threadCount-1) + pause_cpu(); + } + + dll_export TaskScheduler::Thread* TaskScheduler::thread() { + return thread_local_thread; + } + + dll_export TaskScheduler::Thread* TaskScheduler::swapThread(Thread* thread) + { + Thread* old = thread_local_thread; + thread_local_thread = thread; + return old; + } + + dll_export bool TaskScheduler::wait() + { + Thread* thread = TaskScheduler::thread(); + if (thread == nullptr) return true; + while (thread->tasks.execute_local_internal(*thread,thread->task)) {}; + return thread->scheduler->cancellingException == nullptr; + } + +// -- GODOT start -- +// std::exception_ptr TaskScheduler::thread_loop(size_t threadIndex) + void TaskScheduler::thread_loop(size_t threadIndex) +// -- GODOT end -- + { + /* allocate thread structure */ + std::unique_ptr<Thread> mthread(new Thread(threadIndex,this)); // too large for stack allocation + Thread& thread = *mthread; + threadLocal[threadIndex].store(&thread); + Thread* oldThread = swapThread(&thread); + + /* main thread loop */ + while (anyTasksRunning) + { + steal_loop(thread, + [&] () { return anyTasksRunning > 0; }, + [&] () { + anyTasksRunning++; + while (thread.tasks.execute_local_internal(thread,nullptr)); + anyTasksRunning--; + }); + } + threadLocal[threadIndex].store(nullptr); + swapThread(oldThread); + + /* remember exception to throw */ + // -- GODOT start -- + // std::exception_ptr except = nullptr; + // if (cancellingException != nullptr) except = cancellingException; + // -- GODOT end -- + /* wait for all threads to terminate */ + threadCounter--; +#if defined(__WIN32__) + size_t loopIndex = 1; +#endif +#define LOOP_YIELD_THRESHOLD (4096) + while (threadCounter > 0) { +#if defined(__WIN32__) + if ((loopIndex % LOOP_YIELD_THRESHOLD) == 0) + yield(); + else + _mm_pause(); + loopIndex++; +#else + yield(); +#endif + } + // -- GODOT start -- + // return except; + return; + // -- GODOT end -- + } + + bool TaskScheduler::steal_from_other_threads(Thread& thread) + { + const size_t threadIndex = thread.threadIndex; + const size_t threadCount = this->threadCounter; + + for (size_t i=1; i<threadCount; i++) + { + pause_cpu(32); + size_t otherThreadIndex = threadIndex+i; + if (otherThreadIndex >= threadCount) otherThreadIndex -= threadCount; + + Thread* othread = threadLocal[otherThreadIndex].load(); + if (!othread) + continue; + + if (othread->tasks.steal(thread)) + return true; + } + + return false; + } + + dll_export void TaskScheduler::startThreads() { + threadPool->startThreads(); + } + + dll_export void TaskScheduler::addScheduler(const Ref<TaskScheduler>& scheduler) { + threadPool->add(scheduler); + } + + dll_export void TaskScheduler::removeScheduler(const Ref<TaskScheduler>& scheduler) { + threadPool->remove(scheduler); + } + + RTC_NAMESPACE_END +} |