416 lines
11 KiB
C++
416 lines
11 KiB
C++
// Copyright 2009-2020 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;
|
|
try {
|
|
if (thread.scheduler->cancellingException == nullptr)
|
|
closure->execute();
|
|
} catch (...) {
|
|
if (thread.scheduler->cancellingException == nullptr)
|
|
thread.scheduler->cancellingException = std::current_exception();
|
|
}
|
|
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();
|
|
std::exception_ptr except = thread_loop(threadIndex);
|
|
if (except != nullptr) std::rethrow_exception(except);
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
std::exception_ptr TaskScheduler::thread_loop(size_t threadIndex)
|
|
{
|
|
/* 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 */
|
|
std::exception_ptr except = nullptr;
|
|
if (cancellingException != nullptr) except = cancellingException;
|
|
|
|
/* 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
|
|
// -- GODOT start --
|
|
#if !defined(__MINGW32__)
|
|
// -- GODOT end --
|
|
_mm_pause();
|
|
// -- GODOT start --
|
|
#else
|
|
__builtin_ia32_pause();
|
|
#endif
|
|
// -- GODOT end --
|
|
loopIndex++;
|
|
#else
|
|
yield();
|
|
#endif
|
|
}
|
|
return except;
|
|
}
|
|
|
|
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
|
|
}
|