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set cpu affinity of JobSystem's threads

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this is to try to prevent threads from bouncing
between cores
This commit is contained in:
Pixelflinger
2018-12-10 22:27:57 -08:00
committed by Mathias Agopian
parent 025f4a54f5
commit e624dff037
3 changed files with 30 additions and 16 deletions
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24
libs/utils/src/JobSystem.cpp
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@@ -103,6 +103,15 @@ void JobSystem::setThreadAffinity(uint32_t mask) noexcept {
#endif
}
void JobSystem::setThreadAffinityById(size_t id) noexcept {
#if defined(__linux__)
cpu_set_t set;
CPU_ZERO(&set);
CPU_SET(id, &set);
sched_setaffinity(gettid(), sizeof(set), &set);
#endif
}
JobSystem::JobSystem(size_t threadCount, size_t adoptableThreadsCount) noexcept
: mJobPool("JobSystem Job pool", MAX_JOB_COUNT * sizeof(Job)),
mJobStorageBase(static_cast<Job *>(mJobPool.getAllocator().getCurrent()))
@@ -138,7 +147,7 @@ JobSystem::JobSystem(size_t threadCount, size_t adoptableThreadsCount) noexcept
for (size_t i = 0, n = states.size(); i < n; i++) {
auto& state = states[i];
state.rndGen = default_random_engine(rd());
state.mask = uint32_t(1UL << i);
state.id = (uint32_t)i;
state.js = this;
if (i < hardwareThreadCount) {
// don't start a thread of adoptable thread slots
@@ -266,19 +275,24 @@ bool JobSystem::execute(JobSystem::ThreadState& state) noexcept {
return job != nullptr;
}
void JobSystem::loop(ThreadState* threadState) noexcept {
void JobSystem::loop(ThreadState* state) noexcept {
setThreadName("JobSystem::loop");
setThreadPriority(Priority::DISPLAY);
// set a CPU affinity on each of our JobSystem thread to prevent them from jumping from core
// to core. On Android, it looks like the affinity needs to be reset from time to time.
setThreadAffinityById(state->id);
// record our work queue to thread-local storage
sThreadState = threadState;
sThreadState = state;
// run our main loop...
do {
if (!execute(*threadState)) {
if (!execute(*state)) {
std::unique_lock<Mutex> lock(mLock);
while (!exitRequested() && !(mActiveJobs.load(std::memory_order_relaxed))) {
mCondition.wait(lock);
setThreadAffinityById(state->id);
}
}
} while (!exitRequested());
@@ -454,7 +468,7 @@ void JobSystem::emancipate() {
io::ostream& operator<<(io::ostream& out, JobSystem const& js) {
for (auto const& item : js.mThreadStates) {
out << size_t(std::log2f(item.mask)) << ": " << item.workQueue.getCount() << io::endl;
out << size_t(item.id) << ": " << item.workQueue.getCount() << io::endl;
}
return out;
}