Merge pull request #3038 from lioncash/docs
kernel/scheduler: Minor changes
This commit is contained in:
commit
04b838c857
2 changed files with 73 additions and 91 deletions
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@ -22,9 +22,9 @@
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namespace Kernel {
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GlobalScheduler::GlobalScheduler(Core::System& system) : system{system} {
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is_reselection_pending = false;
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}
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GlobalScheduler::GlobalScheduler(Core::System& system) : system{system} {}
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GlobalScheduler::~GlobalScheduler() = default;
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void GlobalScheduler::AddThread(SharedPtr<Thread> thread) {
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thread_list.push_back(std::move(thread));
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@ -35,24 +35,11 @@ void GlobalScheduler::RemoveThread(const Thread* thread) {
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thread_list.end());
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}
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/*
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* UnloadThread selects a core and forces it to unload its current thread's context
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*/
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void GlobalScheduler::UnloadThread(s32 core) {
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Scheduler& sched = system.Scheduler(core);
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sched.UnloadThread();
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}
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/*
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* SelectThread takes care of selecting the new scheduled thread.
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* It does it in 3 steps:
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* - First a thread is selected from the top of the priority queue. If no thread
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* is obtained then we move to step two, else we are done.
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* - Second we try to get a suggested thread that's not assigned to any core or
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* that is not the top thread in that core.
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* - Third is no suggested thread is found, we do a second pass and pick a running
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* thread in another core and swap it with its current thread.
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*/
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void GlobalScheduler::SelectThread(u32 core) {
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const auto update_thread = [](Thread* thread, Scheduler& sched) {
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if (thread != sched.selected_thread) {
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@ -114,30 +101,19 @@ void GlobalScheduler::SelectThread(u32 core) {
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update_thread(current_thread, sched);
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}
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/*
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* YieldThread takes a thread and moves it to the back of the it's priority list
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* This operation can be redundant and no scheduling is changed if marked as so.
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*/
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bool GlobalScheduler::YieldThread(Thread* yielding_thread) {
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// Note: caller should use critical section, etc.
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const u32 core_id = static_cast<u32>(yielding_thread->GetProcessorID());
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const u32 priority = yielding_thread->GetPriority();
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// Yield the thread
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ASSERT_MSG(yielding_thread == scheduled_queue[core_id].front(priority),
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"Thread yielding without being in front");
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const Thread* const winner = scheduled_queue[core_id].front(priority);
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ASSERT_MSG(yielding_thread == winner, "Thread yielding without being in front");
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scheduled_queue[core_id].yield(priority);
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Thread* winner = scheduled_queue[core_id].front(priority);
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return AskForReselectionOrMarkRedundant(yielding_thread, winner);
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}
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/*
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* YieldThreadAndBalanceLoad takes a thread and moves it to the back of the it's priority list.
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* Afterwards, tries to pick a suggested thread from the suggested queue that has worse time or
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* a better priority than the next thread in the core.
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* This operation can be redundant and no scheduling is changed if marked as so.
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*/
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bool GlobalScheduler::YieldThreadAndBalanceLoad(Thread* yielding_thread) {
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// Note: caller should check if !thread.IsSchedulerOperationRedundant and use critical section,
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// etc.
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@ -189,12 +165,6 @@ bool GlobalScheduler::YieldThreadAndBalanceLoad(Thread* yielding_thread) {
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return AskForReselectionOrMarkRedundant(yielding_thread, winner);
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}
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/*
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* YieldThreadAndWaitForLoadBalancing takes a thread and moves it out of the scheduling queue
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* and into the suggested queue. If no thread can be squeduled afterwards in that core,
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* a suggested thread is obtained instead.
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* This operation can be redundant and no scheduling is changed if marked as so.
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*/
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bool GlobalScheduler::YieldThreadAndWaitForLoadBalancing(Thread* yielding_thread) {
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// Note: caller should check if !thread.IsSchedulerOperationRedundant and use critical section,
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// etc.
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@ -280,7 +250,7 @@ void GlobalScheduler::PreemptThreads() {
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if (winner->IsRunning()) {
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UnloadThread(winner->GetProcessorID());
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}
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TransferToCore(winner->GetPriority(), core_id, winner);
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TransferToCore(winner->GetPriority(), s32(core_id), winner);
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current_thread =
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winner->GetPriority() <= current_thread->GetPriority() ? winner : current_thread;
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}
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@ -313,7 +283,7 @@ void GlobalScheduler::PreemptThreads() {
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if (winner->IsRunning()) {
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UnloadThread(winner->GetProcessorID());
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}
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TransferToCore(winner->GetPriority(), core_id, winner);
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TransferToCore(winner->GetPriority(), s32(core_id), winner);
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current_thread = winner;
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}
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}
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@ -331,12 +301,12 @@ void GlobalScheduler::Unsuggest(u32 priority, u32 core, Thread* thread) {
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}
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void GlobalScheduler::Schedule(u32 priority, u32 core, Thread* thread) {
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ASSERT_MSG(thread->GetProcessorID() == core, "Thread must be assigned to this core.");
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ASSERT_MSG(thread->GetProcessorID() == s32(core), "Thread must be assigned to this core.");
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scheduled_queue[core].add(thread, priority);
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}
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void GlobalScheduler::SchedulePrepend(u32 priority, u32 core, Thread* thread) {
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ASSERT_MSG(thread->GetProcessorID() == core, "Thread must be assigned to this core.");
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ASSERT_MSG(thread->GetProcessorID() == s32(core), "Thread must be assigned to this core.");
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scheduled_queue[core].add(thread, priority, false);
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}
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@ -368,7 +338,8 @@ void GlobalScheduler::TransferToCore(u32 priority, s32 destination_core, Thread*
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}
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}
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bool GlobalScheduler::AskForReselectionOrMarkRedundant(Thread* current_thread, Thread* winner) {
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bool GlobalScheduler::AskForReselectionOrMarkRedundant(Thread* current_thread,
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const Thread* winner) {
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if (current_thread == winner) {
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current_thread->IncrementYieldCount();
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return true;
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@ -386,8 +357,6 @@ void GlobalScheduler::Shutdown() {
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thread_list.clear();
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}
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GlobalScheduler::~GlobalScheduler() = default;
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Scheduler::Scheduler(Core::System& system, Core::ARM_Interface& cpu_core, u32 core_id)
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: system(system), cpu_core(cpu_core), core_id(core_id) {}
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@ -470,7 +439,7 @@ void Scheduler::SwitchContext() {
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// Load context of new thread
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if (new_thread) {
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ASSERT_MSG(new_thread->GetProcessorID() == this->core_id,
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ASSERT_MSG(new_thread->GetProcessorID() == s32(this->core_id),
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"Thread must be assigned to this core.");
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ASSERT_MSG(new_thread->GetStatus() == ThreadStatus::Ready,
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"Thread must be ready to become running.");
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@ -26,6 +26,7 @@ public:
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explicit GlobalScheduler(Core::System& system);
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~GlobalScheduler();
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/// Adds a new thread to the scheduler
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void AddThread(SharedPtr<Thread> thread);
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@ -37,47 +38,57 @@ public:
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return thread_list;
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}
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// Add a thread to the suggested queue of a cpu core. Suggested threads may be
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// picked if no thread is scheduled to run on the core.
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/**
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* Add a thread to the suggested queue of a cpu core. Suggested threads may be
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* picked if no thread is scheduled to run on the core.
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*/
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void Suggest(u32 priority, u32 core, Thread* thread);
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// Remove a thread to the suggested queue of a cpu core. Suggested threads may be
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// picked if no thread is scheduled to run on the core.
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/**
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* Remove a thread to the suggested queue of a cpu core. Suggested threads may be
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* picked if no thread is scheduled to run on the core.
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*/
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void Unsuggest(u32 priority, u32 core, Thread* thread);
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// Add a thread to the scheduling queue of a cpu core. The thread is added at the
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// back the queue in its priority level
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/**
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* Add a thread to the scheduling queue of a cpu core. The thread is added at the
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* back the queue in its priority level.
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*/
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void Schedule(u32 priority, u32 core, Thread* thread);
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// Add a thread to the scheduling queue of a cpu core. The thread is added at the
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// front the queue in its priority level
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/**
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* Add a thread to the scheduling queue of a cpu core. The thread is added at the
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* front the queue in its priority level.
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*/
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void SchedulePrepend(u32 priority, u32 core, Thread* thread);
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// Reschedule an already scheduled thread based on a new priority
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/// Reschedule an already scheduled thread based on a new priority
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void Reschedule(u32 priority, u32 core, Thread* thread);
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// Unschedule a thread.
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/// Unschedules a thread.
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void Unschedule(u32 priority, u32 core, Thread* thread);
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// Transfers a thread into an specific core. If the destination_core is -1
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// it will be unscheduled from its source code and added into its suggested
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// queue.
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/**
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* Transfers a thread into an specific core. If the destination_core is -1
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* it will be unscheduled from its source code and added into its suggested
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* queue.
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*/
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void TransferToCore(u32 priority, s32 destination_core, Thread* thread);
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/*
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* UnloadThread selects a core and forces it to unload its current thread's context
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*/
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/// Selects a core and forces it to unload its current thread's context
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void UnloadThread(s32 core);
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/*
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* SelectThread takes care of selecting the new scheduled thread.
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* It does it in 3 steps:
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* - First a thread is selected from the top of the priority queue. If no thread
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* is obtained then we move to step two, else we are done.
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* - Second we try to get a suggested thread that's not assigned to any core or
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* that is not the top thread in that core.
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* - Third is no suggested thread is found, we do a second pass and pick a running
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* thread in another core and swap it with its current thread.
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/**
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* Takes care of selecting the new scheduled thread in three steps:
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*
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* 1. First a thread is selected from the top of the priority queue. If no thread
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* is obtained then we move to step two, else we are done.
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*
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* 2. Second we try to get a suggested thread that's not assigned to any core or
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* that is not the top thread in that core.
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*
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* 3. Third is no suggested thread is found, we do a second pass and pick a running
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* thread in another core and swap it with its current thread.
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*/
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void SelectThread(u32 core);
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@ -85,33 +96,37 @@ public:
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return !scheduled_queue[core_id].empty();
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}
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/*
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* YieldThread takes a thread and moves it to the back of the it's priority list
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* This operation can be redundant and no scheduling is changed if marked as so.
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/**
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* Takes a thread and moves it to the back of the it's priority list.
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*
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* @note This operation can be redundant and no scheduling is changed if marked as so.
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*/
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bool YieldThread(Thread* thread);
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/*
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* YieldThreadAndBalanceLoad takes a thread and moves it to the back of the it's priority list.
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/**
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* Takes a thread and moves it to the back of the it's priority list.
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* Afterwards, tries to pick a suggested thread from the suggested queue that has worse time or
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* a better priority than the next thread in the core.
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* This operation can be redundant and no scheduling is changed if marked as so.
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*
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* @note This operation can be redundant and no scheduling is changed if marked as so.
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*/
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bool YieldThreadAndBalanceLoad(Thread* thread);
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/*
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* YieldThreadAndWaitForLoadBalancing takes a thread and moves it out of the scheduling queue
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* and into the suggested queue. If no thread can be squeduled afterwards in that core,
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/**
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* Takes a thread and moves it out of the scheduling queue.
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* and into the suggested queue. If no thread can be scheduled afterwards in that core,
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* a suggested thread is obtained instead.
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* This operation can be redundant and no scheduling is changed if marked as so.
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*
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* @note This operation can be redundant and no scheduling is changed if marked as so.
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*/
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bool YieldThreadAndWaitForLoadBalancing(Thread* thread);
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/*
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* PreemptThreads this operation rotates the scheduling queues of threads at
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* a preemption priority and then does some core rebalancing. Preemption priorities
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* can be found in the array 'preemption_priorities'. This operation happens
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* every 10ms.
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/**
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* Rotates the scheduling queues of threads at a preemption priority and then does
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* some core rebalancing. Preemption priorities can be found in the array
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* 'preemption_priorities'.
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*
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* @note This operation happens every 10ms.
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*/
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void PreemptThreads();
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@ -130,15 +145,15 @@ public:
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void Shutdown();
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private:
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bool AskForReselectionOrMarkRedundant(Thread* current_thread, Thread* winner);
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bool AskForReselectionOrMarkRedundant(Thread* current_thread, const Thread* winner);
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static constexpr u32 min_regular_priority = 2;
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std::array<Common::MultiLevelQueue<Thread*, THREADPRIO_COUNT>, NUM_CPU_CORES> scheduled_queue;
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std::array<Common::MultiLevelQueue<Thread*, THREADPRIO_COUNT>, NUM_CPU_CORES> suggested_queue;
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std::atomic<bool> is_reselection_pending;
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std::atomic<bool> is_reselection_pending{false};
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// `preemption_priorities` are the priority levels at which the global scheduler
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// preempts threads every 10 ms. They are ordered from Core 0 to Core 3
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// The priority levels at which the global scheduler preempts threads every 10 ms. They are
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// ordered from Core 0 to Core 3.
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std::array<u32, NUM_CPU_CORES> preemption_priorities = {59, 59, 59, 62};
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/// Lists all thread ids that aren't deleted/etc.
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@ -181,10 +196,8 @@ public:
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private:
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friend class GlobalScheduler;
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/**
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* Switches the CPU's active thread context to that of the specified thread
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* @param new_thread The thread to switch to
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*/
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/// Switches the CPU's active thread context to that of the specified thread
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void SwitchContext();
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/**
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