mirror of
https://github.com/yuzu-emu/yuzu.git
synced 2025-06-22 08:27:57 -05:00
Implement a new Core Scheduler
This commit is contained in:
Fernando Sahmkow
committed by
FernandoS27
FernandoS27
parent
cab2619aeb
commit
b164d8ee53
@ -3,6 +3,8 @@
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// Refer to the license.txt file included.
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#include <algorithm>
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#include <set>
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#include <unordered_set>
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#include <utility>
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#include "common/assert.h"
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@ -17,57 +19,286 @@
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namespace Kernel {
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std::mutex Scheduler::scheduler_mutex;
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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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}
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Scheduler::Scheduler(Core::System& system, Core::ARM_Interface& cpu_core)
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: cpu_core{cpu_core}, system{system} {}
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void GlobalScheduler::RemoveThread(Thread* thread) {
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thread_list.erase(std::remove(thread_list.begin(), thread_list.end(), thread),
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thread_list.end());
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}
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Scheduler::~Scheduler() {
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for (auto& thread : thread_list) {
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thread->Stop();
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/*
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* SelectThreads, Yield functions originally by TuxSH.
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* licensed under GPLv2 or later under exception provided by the author.
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*/
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void GlobalScheduler::UnloadThread(s32 core) {
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Scheduler& sched = Core::System::GetInstance().Scheduler(core);
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sched.UnloadThread();
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}
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void GlobalScheduler::SelectThread(u32 core) {
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auto update_thread = [](Thread* thread, Scheduler& sched) {
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if (thread != sched.selected_thread) {
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if (thread == nullptr) {
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++sched.idle_selection_count;
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}
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sched.selected_thread = thread;
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}
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sched.context_switch_pending = sched.selected_thread != sched.current_thread;
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std::atomic_thread_fence(std::memory_order_seq_cst);
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};
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Scheduler& sched = Core::System::GetInstance().Scheduler(core);
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Thread* current_thread = nullptr;
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current_thread = scheduled_queue[core].empty() ? nullptr : scheduled_queue[core].front();
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if (!current_thread) {
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Thread* winner = nullptr;
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std::set<s32> sug_cores;
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for (auto thread : suggested_queue[core]) {
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s32 this_core = thread->GetProcessorID();
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Thread* thread_on_core = nullptr;
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if (this_core >= 0) {
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thread_on_core = scheduled_queue[this_core].front();
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}
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if (this_core < 0 || thread != thread_on_core) {
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winner = thread;
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break;
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}
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sug_cores.insert(this_core);
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}
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if (winner && winner->GetPriority() > 2) {
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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, winner);
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current_thread = winner;
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} else {
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for (auto& src_core : sug_cores) {
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auto it = scheduled_queue[src_core].begin();
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it++;
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if (it != scheduled_queue[src_core].end()) {
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Thread* thread_on_core = scheduled_queue[src_core].front();
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Thread* to_change = *it;
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if (thread_on_core->IsRunning() || to_change->IsRunning()) {
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UnloadThread(src_core);
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}
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TransferToCore(thread_on_core->GetPriority(), core, thread_on_core);
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current_thread = thread_on_core;
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}
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}
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}
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}
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update_thread(current_thread, sched);
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}
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void GlobalScheduler::SelectThreads() {
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auto update_thread = [](Thread* thread, Scheduler& sched) {
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if (thread != sched.selected_thread) {
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if (thread == nullptr) {
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++sched.idle_selection_count;
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}
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sched.selected_thread = thread;
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}
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sched.context_switch_pending = sched.selected_thread != sched.current_thread;
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std::atomic_thread_fence(std::memory_order_seq_cst);
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};
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auto& system = Core::System::GetInstance();
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std::unordered_set<Thread*> picked_threads;
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// This maintain the "current thread is on front of queue" invariant
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std::array<Thread*, NUM_CPU_CORES> current_threads;
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for (u32 i = 0; i < NUM_CPU_CORES; i++) {
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Scheduler& sched = system.Scheduler(i);
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current_threads[i] = scheduled_queue[i].empty() ? nullptr : scheduled_queue[i].front();
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if (current_threads[i])
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picked_threads.insert(current_threads[i]);
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update_thread(current_threads[i], sched);
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}
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// Do some load-balancing. Allow second pass.
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std::array<Thread*, NUM_CPU_CORES> current_threads_2 = current_threads;
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for (u32 i = 0; i < NUM_CPU_CORES; i++) {
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if (!scheduled_queue[i].empty()) {
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continue;
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}
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Thread* winner = nullptr;
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for (auto thread : suggested_queue[i]) {
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if (thread->GetProcessorID() < 0 || thread != current_threads[i]) {
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if (picked_threads.count(thread) == 0 && !thread->IsRunning()) {
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winner = thread;
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break;
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}
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}
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}
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if (winner) {
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TransferToCore(winner->GetPriority(), i, winner);
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current_threads_2[i] = winner;
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picked_threads.insert(winner);
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}
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}
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// See which to-be-current threads have changed & update accordingly
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for (u32 i = 0; i < NUM_CPU_CORES; i++) {
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Scheduler& sched = system.Scheduler(i);
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if (current_threads_2[i] != current_threads[i]) {
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update_thread(current_threads_2[i], sched);
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}
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}
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reselection_pending.store(false, std::memory_order_release);
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}
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void GlobalScheduler::YieldThread(Thread* yielding_thread) {
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// Note: caller should use critical section, etc.
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u32 core_id = static_cast<u32>(yielding_thread->GetProcessorID());
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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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scheduled_queue[core_id].yield(priority);
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Thread* winner = scheduled_queue[core_id].front(priority);
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AskForReselectionOrMarkRedundant(yielding_thread, winner);
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}
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void 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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u32 core_id = static_cast<u32>(yielding_thread->GetProcessorID());
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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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scheduled_queue[core_id].yield(priority);
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std::array<Thread*, NUM_CPU_CORES> current_threads;
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for (u32 i = 0; i < NUM_CPU_CORES; i++) {
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current_threads[i] = scheduled_queue[i].empty() ? nullptr : scheduled_queue[i].front();
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}
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Thread* next_thread = scheduled_queue[core_id].front(priority);
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Thread* winner = nullptr;
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for (auto& thread : suggested_queue[core_id]) {
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s32 source_core = thread->GetProcessorID();
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if (source_core >= 0) {
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if (current_threads[source_core] != nullptr) {
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if (thread == current_threads[source_core] ||
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current_threads[source_core]->GetPriority() < min_regular_priority)
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continue;
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}
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if (next_thread->GetLastRunningTicks() >= thread->GetLastRunningTicks() ||
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next_thread->GetPriority() < thread->GetPriority()) {
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if (thread->GetPriority() <= priority) {
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winner = thread;
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break;
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}
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}
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}
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}
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if (winner != nullptr) {
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if (winner != yielding_thread) {
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if (winner->IsRunning())
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UnloadThread(winner->GetProcessorID());
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TransferToCore(winner->GetPriority(), core_id, winner);
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}
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} else {
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winner = next_thread;
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}
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AskForReselectionOrMarkRedundant(yielding_thread, winner);
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}
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void 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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Thread* winner = nullptr;
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u32 core_id = static_cast<u32>(yielding_thread->GetProcessorID());
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// Remove the thread from its scheduled mlq, put it on the corresponding "suggested" one instead
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TransferToCore(yielding_thread->GetPriority(), -1, yielding_thread);
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// If the core is idle, perform load balancing, excluding the threads that have just used this
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// function...
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if (scheduled_queue[core_id].empty()) {
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// Here, "current_threads" is calculated after the ""yield"", unlike yield -1
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std::array<Thread*, NUM_CPU_CORES> current_threads;
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for (u32 i = 0; i < NUM_CPU_CORES; i++) {
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current_threads[i] = scheduled_queue[i].empty() ? nullptr : scheduled_queue[i].front();
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}
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for (auto& thread : suggested_queue[core_id]) {
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s32 source_core = thread->GetProcessorID();
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if (source_core < 0 || thread == current_threads[source_core])
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continue;
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if (current_threads[source_core] == nullptr ||
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current_threads[source_core]->GetPriority() >= min_regular_priority) {
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winner = thread;
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}
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break;
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}
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if (winner != nullptr) {
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if (winner != yielding_thread) {
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if (winner->IsRunning())
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UnloadThread(winner->GetProcessorID());
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TransferToCore(winner->GetPriority(), core_id, winner);
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}
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} else {
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winner = yielding_thread;
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}
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}
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AskForReselectionOrMarkRedundant(yielding_thread, winner);
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}
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void GlobalScheduler::AskForReselectionOrMarkRedundant(Thread* current_thread, Thread* winner) {
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if (current_thread == winner) {
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// Nintendo (not us) has a nullderef bug on current_thread->owner, but which is never
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// triggered.
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// current_thread->SetRedundantSchedulerOperation();
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} else {
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reselection_pending.store(true, std::memory_order_release);
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}
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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 id)
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: system(system), cpu_core(cpu_core), id(id) {}
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Scheduler::~Scheduler() {}
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bool Scheduler::HaveReadyThreads() const {
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std::lock_guard lock{scheduler_mutex};
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return !ready_queue.empty();
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return system.GlobalScheduler().HaveReadyThreads(id);
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}
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Thread* Scheduler::GetCurrentThread() const {
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return current_thread.get();
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}
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Thread* Scheduler::GetSelectedThread() const {
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return selected_thread.get();
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}
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void Scheduler::SelectThreads() {
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system.GlobalScheduler().SelectThread(id);
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}
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u64 Scheduler::GetLastContextSwitchTicks() const {
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return last_context_switch_time;
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}
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Thread* Scheduler::PopNextReadyThread() {
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Thread* next = nullptr;
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Thread* thread = GetCurrentThread();
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if (thread && thread->GetStatus() == ThreadStatus::Running) {
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if (ready_queue.empty()) {
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return thread;
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}
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// We have to do better than the current thread.
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// This call returns null when that's not possible.
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next = ready_queue.front();
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if (next == nullptr || next->GetPriority() >= thread->GetPriority()) {
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next = thread;
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}
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} else {
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if (ready_queue.empty()) {
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return nullptr;
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}
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next = ready_queue.front();
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}
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return next;
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void Scheduler::TryDoContextSwitch() {
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if (context_switch_pending)
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SwitchContext();
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}
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void Scheduler::SwitchContext(Thread* new_thread) {
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Thread* previous_thread = GetCurrentThread();
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Process* const previous_process = system.Kernel().CurrentProcess();
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void Scheduler::UnloadThread() {
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Thread* const previous_thread = GetCurrentThread();
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Process* const previous_process = Core::CurrentProcess();
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UpdateLastContextSwitchTime(previous_thread, previous_process);
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@ -80,23 +311,51 @@ void Scheduler::SwitchContext(Thread* new_thread) {
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if (previous_thread->GetStatus() == ThreadStatus::Running) {
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// This is only the case when a reschedule is triggered without the current thread
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// yielding execution (i.e. an event triggered, system core time-sliced, etc)
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ready_queue.add(previous_thread, previous_thread->GetPriority(), false);
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previous_thread->SetStatus(ThreadStatus::Ready);
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}
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previous_thread->SetIsRunning(false);
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}
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current_thread = nullptr;
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}
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void Scheduler::SwitchContext() {
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Thread* const previous_thread = GetCurrentThread();
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Thread* const new_thread = GetSelectedThread();
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context_switch_pending = false;
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if (new_thread == previous_thread)
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return;
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Process* const previous_process = Core::CurrentProcess();
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UpdateLastContextSwitchTime(previous_thread, previous_process);
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// Save context for previous thread
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if (previous_thread) {
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cpu_core.SaveContext(previous_thread->GetContext());
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// Save the TPIDR_EL0 system register in case it was modified.
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previous_thread->SetTPIDR_EL0(cpu_core.GetTPIDR_EL0());
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if (previous_thread->GetStatus() == ThreadStatus::Running) {
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// This is only the case when a reschedule is triggered without the current thread
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// yielding execution (i.e. an event triggered, system core time-sliced, etc)
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previous_thread->SetStatus(ThreadStatus::Ready);
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}
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previous_thread->SetIsRunning(false);
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}
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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->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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// Cancel any outstanding wakeup events for this thread
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new_thread->CancelWakeupTimer();
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current_thread = new_thread;
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ready_queue.remove(new_thread, new_thread->GetPriority());
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new_thread->SetStatus(ThreadStatus::Running);
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new_thread->SetIsRunning(true);
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auto* const thread_owner_process = current_thread->GetOwnerProcess();
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if (previous_process != thread_owner_process) {
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@ -116,7 +375,7 @@ void Scheduler::SwitchContext(Thread* new_thread) {
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void Scheduler::UpdateLastContextSwitchTime(Thread* thread, Process* process) {
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const u64 prev_switch_ticks = last_context_switch_time;
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const u64 most_recent_switch_ticks = system.CoreTiming().GetTicks();
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const u64 most_recent_switch_ticks = Core::System::GetInstance().CoreTiming().GetTicks();
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const u64 update_ticks = most_recent_switch_ticks - prev_switch_ticks;
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if (thread != nullptr) {
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@ -130,124 +389,4 @@ void Scheduler::UpdateLastContextSwitchTime(Thread* thread, Process* process) {
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last_context_switch_time = most_recent_switch_ticks;
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}
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void Scheduler::Reschedule() {
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std::lock_guard lock{scheduler_mutex};
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Thread* cur = GetCurrentThread();
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Thread* next = PopNextReadyThread();
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if (cur && next) {
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LOG_TRACE(Kernel, "context switch {} -> {}", cur->GetObjectId(), next->GetObjectId());
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} else if (cur) {
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LOG_TRACE(Kernel, "context switch {} -> idle", cur->GetObjectId());
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} else if (next) {
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LOG_TRACE(Kernel, "context switch idle -> {}", next->GetObjectId());
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}
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SwitchContext(next);
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}
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void Scheduler::AddThread(SharedPtr<Thread> thread) {
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std::lock_guard lock{scheduler_mutex};
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thread_list.push_back(std::move(thread));
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}
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void Scheduler::RemoveThread(Thread* thread) {
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std::lock_guard lock{scheduler_mutex};
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thread_list.erase(std::remove(thread_list.begin(), thread_list.end(), thread),
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thread_list.end());
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}
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void Scheduler::ScheduleThread(Thread* thread, u32 priority) {
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std::lock_guard lock{scheduler_mutex};
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ASSERT(thread->GetStatus() == ThreadStatus::Ready);
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ready_queue.add(thread, priority);
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}
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void Scheduler::UnscheduleThread(Thread* thread, u32 priority) {
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std::lock_guard lock{scheduler_mutex};
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ASSERT(thread->GetStatus() == ThreadStatus::Ready);
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ready_queue.remove(thread, priority);
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}
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void Scheduler::SetThreadPriority(Thread* thread, u32 priority) {
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std::lock_guard lock{scheduler_mutex};
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if (thread->GetPriority() == priority) {
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return;
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}
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// If thread was ready, adjust queues
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if (thread->GetStatus() == ThreadStatus::Ready)
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ready_queue.adjust(thread, thread->GetPriority(), priority);
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}
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Thread* Scheduler::GetNextSuggestedThread(u32 core, u32 maximum_priority) const {
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std::lock_guard lock{scheduler_mutex};
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const u32 mask = 1U << core;
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for (auto* thread : ready_queue) {
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if ((thread->GetAffinityMask() & mask) != 0 && thread->GetPriority() < maximum_priority) {
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return thread;
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}
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}
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return nullptr;
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}
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||||
void Scheduler::YieldWithoutLoadBalancing(Thread* thread) {
|
||||
ASSERT(thread != nullptr);
|
||||
// Avoid yielding if the thread isn't even running.
|
||||
ASSERT(thread->GetStatus() == ThreadStatus::Running);
|
||||
|
||||
// Sanity check that the priority is valid
|
||||
ASSERT(thread->GetPriority() < THREADPRIO_COUNT);
|
||||
|
||||
// Yield this thread -- sleep for zero time and force reschedule to different thread
|
||||
GetCurrentThread()->Sleep(0);
|
||||
}
|
||||
|
||||
void Scheduler::YieldWithLoadBalancing(Thread* thread) {
|
||||
ASSERT(thread != nullptr);
|
||||
const auto priority = thread->GetPriority();
|
||||
const auto core = static_cast<u32>(thread->GetProcessorID());
|
||||
|
||||
// Avoid yielding if the thread isn't even running.
|
||||
ASSERT(thread->GetStatus() == ThreadStatus::Running);
|
||||
|
||||
// Sanity check that the priority is valid
|
||||
ASSERT(priority < THREADPRIO_COUNT);
|
||||
|
||||
// Sleep for zero time to be able to force reschedule to different thread
|
||||
GetCurrentThread()->Sleep(0);
|
||||
|
||||
Thread* suggested_thread = nullptr;
|
||||
|
||||
// Search through all of the cpu cores (except this one) for a suggested thread.
|
||||
// Take the first non-nullptr one
|
||||
for (unsigned cur_core = 0; cur_core < Core::NUM_CPU_CORES; ++cur_core) {
|
||||
const auto res =
|
||||
system.CpuCore(cur_core).Scheduler().GetNextSuggestedThread(core, priority);
|
||||
|
||||
// If scheduler provides a suggested thread
|
||||
if (res != nullptr) {
|
||||
// And its better than the current suggested thread (or is the first valid one)
|
||||
if (suggested_thread == nullptr ||
|
||||
suggested_thread->GetPriority() > res->GetPriority()) {
|
||||
suggested_thread = res;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// If a suggested thread was found, queue that for this core
|
||||
if (suggested_thread != nullptr)
|
||||
suggested_thread->ChangeCore(core, suggested_thread->GetAffinityMask());
|
||||
}
|
||||
|
||||
void Scheduler::YieldAndWaitForLoadBalancing(Thread* thread) {
|
||||
UNIMPLEMENTED_MSG("Wait for load balancing thread yield type is not implemented!");
|
||||
}
|
||||
|
||||
} // namespace Kernel
|
||||
|
||||
Reference in New Issue
Block a user