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scheduler: Only work steal higher priority threads from other cores

This commit is contained in:
Zach Hilman 2018-12-03 17:29:21 -05:00
parent 3476830b26
commit b5af41a07b
3 changed files with 24 additions and 35 deletions

View File

@ -170,16 +170,6 @@ void Scheduler::UnscheduleThread(Thread* thread, u32 priority) {
ready_queue.remove(priority, thread);
}
void Scheduler::MoveThreadToBackOfPriorityQueue(Thread* thread, u32 priority) {
std::lock_guard<std::mutex> lock(scheduler_mutex);
// Thread is not in queue
ASSERT(ready_queue.contains(thread) != -1);
ready_queue.remove(priority, thread);
ready_queue.push_back(priority, thread);
}
void Scheduler::SetThreadPriority(Thread* thread, u32 priority) {
std::lock_guard<std::mutex> lock(scheduler_mutex);
@ -190,12 +180,13 @@ void Scheduler::SetThreadPriority(Thread* thread, u32 priority) {
ready_queue.prepare(priority);
}
Thread* Scheduler::GetNextSuggestedThread(u32 core) const {
Thread* Scheduler::GetNextSuggestedThread(u32 core, u32 maximum_priority) const {
std::lock_guard<std::mutex> lock(scheduler_mutex);
const u32 mask = 1U << core;
return ready_queue.get_first_filter(
[mask](Thread const* thread) { return (thread->GetAffinityMask() & mask) != 0; });
return ready_queue.get_first_filter([mask, maximum_priority](Thread const* thread) {
return (thread->GetAffinityMask() & mask) != 0 && thread->GetPriority() < maximum_priority;
});
}
void Scheduler::YieldWithoutLoadBalancing(Thread* thread) {
@ -206,9 +197,10 @@ void Scheduler::YieldWithoutLoadBalancing(Thread* thread) {
// Sanity check that the priority is valid
ASSERT(thread->GetPriority() < THREADPRIO_COUNT);
// Yield this thread
// Yield this thread -- sleep for zero time and force reschedule to different thread
WaitCurrentThread_Sleep();
GetCurrentThread()->WakeAfterDelay(0);
Reschedule();
MoveThreadToBackOfPriorityQueue(thread, thread->GetPriority());
}
void Scheduler::YieldWithLoadBalancing(Thread* thread) {
@ -222,9 +214,9 @@ void Scheduler::YieldWithLoadBalancing(Thread* thread) {
// Sanity check that the priority is valid
ASSERT(priority < THREADPRIO_COUNT);
// Reschedule thread to end of queue.
Reschedule();
MoveThreadToBackOfPriorityQueue(thread, priority);
// Sleep for zero time to be able to force reschedule to different thread
WaitCurrentThread_Sleep();
GetCurrentThread()->WakeAfterDelay(0);
Thread* suggested_thread = nullptr;
@ -235,16 +227,20 @@ void Scheduler::YieldWithLoadBalancing(Thread* thread) {
continue;
const auto res =
Core::System::GetInstance().CpuCore(cur_core).Scheduler().GetNextSuggestedThread(core);
if (res != nullptr) {
Core::System::GetInstance().CpuCore(cur_core).Scheduler().GetNextSuggestedThread(
core, priority);
if (res != nullptr &&
(suggested_thread == nullptr || suggested_thread->GetPriority() > res->GetPriority())) {
suggested_thread = res;
break;
}
}
// If a suggested thread was found, queue that for this core
if (suggested_thread != nullptr)
suggested_thread->ChangeCore(core, suggested_thread->GetAffinityMask());
// Perform actual yielding.
Reschedule();
}
void Scheduler::YieldAndWaitForLoadBalancing(Thread* thread) {

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@ -48,14 +48,11 @@ public:
/// Unschedules a thread that was already scheduled
void UnscheduleThread(Thread* thread, u32 priority);
/// Moves a thread to the back of the current priority queue
void MoveThreadToBackOfPriorityQueue(Thread* thread, u32 priority);
/// Sets the priority of a thread in the scheduler
void SetThreadPriority(Thread* thread, u32 priority);
/// Gets the next suggested thread for load balancing
Thread* GetNextSuggestedThread(u32 core) const;
Thread* GetNextSuggestedThread(u32 core, u32 minimum_priority) const;
/**
* YieldWithoutLoadBalancing -- analogous to normal yield on a system

View File

@ -984,20 +984,16 @@ static void SleepThread(s64 nanoseconds) {
scheduler.YieldAndWaitForLoadBalancing(GetCurrentThread());
break;
default:
UNREACHABLE_MSG(
"Unimplemented sleep yield type '{:016X}'! Falling back to forced reschedule...",
nanoseconds);
UNREACHABLE_MSG("Unimplemented sleep yield type '{:016X}'!", nanoseconds);
}
} else {
// Sleep current thread and check for next thread to schedule
WaitCurrentThread_Sleep();
nanoseconds = 0;
// Create an event to wake the thread up after the specified nanosecond delay has passed
GetCurrentThread()->WakeAfterDelay(nanoseconds);
}
// Sleep current thread and check for next thread to schedule
WaitCurrentThread_Sleep();
// Create an event to wake the thread up after the specified nanosecond delay has passed
GetCurrentThread()->WakeAfterDelay(nanoseconds);
Core::System::GetInstance().PrepareReschedule();
}