From b164d8ee536dba526f9da2083433d529daf7b37b Mon Sep 17 00:00:00 2001
From: Fernando Sahmkow <fsahmkow27@gmail.com>
Date: Fri, 29 Mar 2019 17:01:17 -0400
Subject: [PATCH] Implement a new Core Scheduler
---
src/core/hle/kernel/scheduler.cpp | 455 +++++++++++++++++++-----------
src/core/hle/kernel/scheduler.h | 234 +++++++--------
2 files changed, 421 insertions(+), 268 deletions(-)
diff --git a/src/core/hle/kernel/scheduler.cpp b/src/core/hle/kernel/scheduler.cpp
index e8447b69a1..878aeed6d6 100644
--- a/src/core/hle/kernel/scheduler.cpp
+++ b/src/core/hle/kernel/scheduler.cpp
@@ -3,6 +3,8 @@
// Refer to the license.txt file included.
#include <algorithm>
+#include <set>
+#include <unordered_set>
#include <utility>
#include "common/assert.h"
@@ -17,57 +19,286 @@
namespace Kernel {
-std::mutex Scheduler::scheduler_mutex;
+void GlobalScheduler::AddThread(SharedPtr<Thread> thread) {
+ thread_list.push_back(std::move(thread));
+}
-Scheduler::Scheduler(Core::System& system, Core::ARM_Interface& cpu_core)
- : cpu_core{cpu_core}, system{system} {}
+void GlobalScheduler::RemoveThread(Thread* thread) {
+ thread_list.erase(std::remove(thread_list.begin(), thread_list.end(), thread),
+ thread_list.end());
+}
-Scheduler::~Scheduler() {
- for (auto& thread : thread_list) {
- thread->Stop();
+/*
+ * SelectThreads, Yield functions originally by TuxSH.
+ * licensed under GPLv2 or later under exception provided by the author.
+ */
+
+void GlobalScheduler::UnloadThread(s32 core) {
+ Scheduler& sched = Core::System::GetInstance().Scheduler(core);
+ sched.UnloadThread();
+}
+
+void GlobalScheduler::SelectThread(u32 core) {
+ auto update_thread = [](Thread* thread, Scheduler& sched) {
+ if (thread != sched.selected_thread) {
+ if (thread == nullptr) {
+ ++sched.idle_selection_count;
+ }
+ sched.selected_thread = thread;
+ }
+ sched.context_switch_pending = sched.selected_thread != sched.current_thread;
+ std::atomic_thread_fence(std::memory_order_seq_cst);
+ };
+ Scheduler& sched = Core::System::GetInstance().Scheduler(core);
+ Thread* current_thread = nullptr;
+ current_thread = scheduled_queue[core].empty() ? nullptr : scheduled_queue[core].front();
+ if (!current_thread) {
+ Thread* winner = nullptr;
+ std::set<s32> sug_cores;
+ for (auto thread : suggested_queue[core]) {
+ s32 this_core = thread->GetProcessorID();
+ Thread* thread_on_core = nullptr;
+ if (this_core >= 0) {
+ thread_on_core = scheduled_queue[this_core].front();
+ }
+ if (this_core < 0 || thread != thread_on_core) {
+ winner = thread;
+ break;
+ }
+ sug_cores.insert(this_core);
+ }
+ if (winner && winner->GetPriority() > 2) {
+ if (winner->IsRunning()) {
+ UnloadThread(winner->GetProcessorID());
+ }
+ TransferToCore(winner->GetPriority(), core, winner);
+ current_thread = winner;
+ } else {
+ for (auto& src_core : sug_cores) {
+ auto it = scheduled_queue[src_core].begin();
+ it++;
+ if (it != scheduled_queue[src_core].end()) {
+ Thread* thread_on_core = scheduled_queue[src_core].front();
+ Thread* to_change = *it;
+ if (thread_on_core->IsRunning() || to_change->IsRunning()) {
+ UnloadThread(src_core);
+ }
+ TransferToCore(thread_on_core->GetPriority(), core, thread_on_core);
+ current_thread = thread_on_core;
+ }
+ }
+ }
+ }
+ update_thread(current_thread, sched);
+}
+
+void GlobalScheduler::SelectThreads() {
+ auto update_thread = [](Thread* thread, Scheduler& sched) {
+ if (thread != sched.selected_thread) {
+ if (thread == nullptr) {
+ ++sched.idle_selection_count;
+ }
+ sched.selected_thread = thread;
+ }
+ sched.context_switch_pending = sched.selected_thread != sched.current_thread;
+ std::atomic_thread_fence(std::memory_order_seq_cst);
+ };
+
+ auto& system = Core::System::GetInstance();
+
+ std::unordered_set<Thread*> picked_threads;
+ // This maintain the "current thread is on front of queue" invariant
+ std::array<Thread*, NUM_CPU_CORES> current_threads;
+ for (u32 i = 0; i < NUM_CPU_CORES; i++) {
+ Scheduler& sched = system.Scheduler(i);
+ current_threads[i] = scheduled_queue[i].empty() ? nullptr : scheduled_queue[i].front();
+ if (current_threads[i])
+ picked_threads.insert(current_threads[i]);
+ update_thread(current_threads[i], sched);
+ }
+
+ // Do some load-balancing. Allow second pass.
+ std::array<Thread*, NUM_CPU_CORES> current_threads_2 = current_threads;
+ for (u32 i = 0; i < NUM_CPU_CORES; i++) {
+ if (!scheduled_queue[i].empty()) {
+ continue;
+ }
+ Thread* winner = nullptr;
+ for (auto thread : suggested_queue[i]) {
+ if (thread->GetProcessorID() < 0 || thread != current_threads[i]) {
+ if (picked_threads.count(thread) == 0 && !thread->IsRunning()) {
+ winner = thread;
+ break;
+ }
+ }
+ }
+ if (winner) {
+ TransferToCore(winner->GetPriority(), i, winner);
+ current_threads_2[i] = winner;
+ picked_threads.insert(winner);
+ }
+ }
+
+ // See which to-be-current threads have changed & update accordingly
+ for (u32 i = 0; i < NUM_CPU_CORES; i++) {
+ Scheduler& sched = system.Scheduler(i);
+ if (current_threads_2[i] != current_threads[i]) {
+ update_thread(current_threads_2[i], sched);
+ }
+ }
+
+ reselection_pending.store(false, std::memory_order_release);
+}
+
+void GlobalScheduler::YieldThread(Thread* yielding_thread) {
+ // Note: caller should use critical section, etc.
+ u32 core_id = static_cast<u32>(yielding_thread->GetProcessorID());
+ u32 priority = yielding_thread->GetPriority();
+
+ // Yield the thread
+ ASSERT_MSG(yielding_thread == scheduled_queue[core_id].front(priority),
+ "Thread yielding without being in front");
+ scheduled_queue[core_id].yield(priority);
+
+ Thread* winner = scheduled_queue[core_id].front(priority);
+ AskForReselectionOrMarkRedundant(yielding_thread, winner);
+}
+
+void GlobalScheduler::YieldThreadAndBalanceLoad(Thread* yielding_thread) {
+ // Note: caller should check if !thread.IsSchedulerOperationRedundant and use critical section,
+ // etc.
+ u32 core_id = static_cast<u32>(yielding_thread->GetProcessorID());
+ u32 priority = yielding_thread->GetPriority();
+
+ // Yield the thread
+ ASSERT_MSG(yielding_thread == scheduled_queue[core_id].front(priority),
+ "Thread yielding without being in front");
+ scheduled_queue[core_id].yield(priority);
+
+ std::array<Thread*, NUM_CPU_CORES> current_threads;
+ for (u32 i = 0; i < NUM_CPU_CORES; i++) {
+ current_threads[i] = scheduled_queue[i].empty() ? nullptr : scheduled_queue[i].front();
+ }
+
+ Thread* next_thread = scheduled_queue[core_id].front(priority);
+ Thread* winner = nullptr;
+ for (auto& thread : suggested_queue[core_id]) {
+ s32 source_core = thread->GetProcessorID();
+ if (source_core >= 0) {
+ if (current_threads[source_core] != nullptr) {
+ if (thread == current_threads[source_core] ||
+ current_threads[source_core]->GetPriority() < min_regular_priority)
+ continue;
+ }
+ if (next_thread->GetLastRunningTicks() >= thread->GetLastRunningTicks() ||
+ next_thread->GetPriority() < thread->GetPriority()) {
+ if (thread->GetPriority() <= priority) {
+ winner = thread;
+ break;
+ }
+ }
+ }
+ }
+
+ if (winner != nullptr) {
+ if (winner != yielding_thread) {
+ if (winner->IsRunning())
+ UnloadThread(winner->GetProcessorID());
+ TransferToCore(winner->GetPriority(), core_id, winner);
+ }
+ } else {
+ winner = next_thread;
+ }
+
+ AskForReselectionOrMarkRedundant(yielding_thread, winner);
+}
+
+void GlobalScheduler::YieldThreadAndWaitForLoadBalancing(Thread* yielding_thread) {
+ // Note: caller should check if !thread.IsSchedulerOperationRedundant and use critical section,
+ // etc.
+ Thread* winner = nullptr;
+ u32 core_id = static_cast<u32>(yielding_thread->GetProcessorID());
+
+ // Remove the thread from its scheduled mlq, put it on the corresponding "suggested" one instead
+ TransferToCore(yielding_thread->GetPriority(), -1, yielding_thread);
+
+ // If the core is idle, perform load balancing, excluding the threads that have just used this
+ // function...
+ if (scheduled_queue[core_id].empty()) {
+ // Here, "current_threads" is calculated after the ""yield"", unlike yield -1
+ std::array<Thread*, NUM_CPU_CORES> current_threads;
+ for (u32 i = 0; i < NUM_CPU_CORES; i++) {
+ current_threads[i] = scheduled_queue[i].empty() ? nullptr : scheduled_queue[i].front();
+ }
+ for (auto& thread : suggested_queue[core_id]) {
+ s32 source_core = thread->GetProcessorID();
+ if (source_core < 0 || thread == current_threads[source_core])
+ continue;
+ if (current_threads[source_core] == nullptr ||
+ current_threads[source_core]->GetPriority() >= min_regular_priority) {
+ winner = thread;
+ }
+ break;
+ }
+ if (winner != nullptr) {
+ if (winner != yielding_thread) {
+ if (winner->IsRunning())
+ UnloadThread(winner->GetProcessorID());
+ TransferToCore(winner->GetPriority(), core_id, winner);
+ }
+ } else {
+ winner = yielding_thread;
+ }
+ }
+
+ AskForReselectionOrMarkRedundant(yielding_thread, winner);
+}
+
+void GlobalScheduler::AskForReselectionOrMarkRedundant(Thread* current_thread, Thread* winner) {
+ if (current_thread == winner) {
+ // Nintendo (not us) has a nullderef bug on current_thread->owner, but which is never
+ // triggered.
+ // current_thread->SetRedundantSchedulerOperation();
+ } else {
+ reselection_pending.store(true, std::memory_order_release);
}
}
+GlobalScheduler::~GlobalScheduler() = default;
+
+Scheduler::Scheduler(Core::System& system, Core::ARM_Interface& cpu_core, u32 id)
+ : system(system), cpu_core(cpu_core), id(id) {}
+
+Scheduler::~Scheduler() {}
+
bool Scheduler::HaveReadyThreads() const {
- std::lock_guard lock{scheduler_mutex};
- return !ready_queue.empty();
+ return system.GlobalScheduler().HaveReadyThreads(id);
}
Thread* Scheduler::GetCurrentThread() const {
return current_thread.get();
}
+Thread* Scheduler::GetSelectedThread() const {
+ return selected_thread.get();
+}
+
+void Scheduler::SelectThreads() {
+ system.GlobalScheduler().SelectThread(id);
+}
+
u64 Scheduler::GetLastContextSwitchTicks() const {
return last_context_switch_time;
}
-Thread* Scheduler::PopNextReadyThread() {
- Thread* next = nullptr;
- Thread* thread = GetCurrentThread();
-
- if (thread && thread->GetStatus() == ThreadStatus::Running) {
- if (ready_queue.empty()) {
- return thread;
- }
- // We have to do better than the current thread.
- // This call returns null when that's not possible.
- next = ready_queue.front();
- if (next == nullptr || next->GetPriority() >= thread->GetPriority()) {
- next = thread;
- }
- } else {
- if (ready_queue.empty()) {
- return nullptr;
- }
- next = ready_queue.front();
- }
-
- return next;
+void Scheduler::TryDoContextSwitch() {
+ if (context_switch_pending)
+ SwitchContext();
}
-void Scheduler::SwitchContext(Thread* new_thread) {
- Thread* previous_thread = GetCurrentThread();
- Process* const previous_process = system.Kernel().CurrentProcess();
+void Scheduler::UnloadThread() {
+ Thread* const previous_thread = GetCurrentThread();
+ Process* const previous_process = Core::CurrentProcess();
UpdateLastContextSwitchTime(previous_thread, previous_process);
@@ -80,23 +311,51 @@ void Scheduler::SwitchContext(Thread* new_thread) {
if (previous_thread->GetStatus() == ThreadStatus::Running) {
// This is only the case when a reschedule is triggered without the current thread
// yielding execution (i.e. an event triggered, system core time-sliced, etc)
- ready_queue.add(previous_thread, previous_thread->GetPriority(), false);
previous_thread->SetStatus(ThreadStatus::Ready);
}
+ previous_thread->SetIsRunning(false);
+ }
+ current_thread = nullptr;
+}
+
+void Scheduler::SwitchContext() {
+ Thread* const previous_thread = GetCurrentThread();
+ Thread* const new_thread = GetSelectedThread();
+
+ context_switch_pending = false;
+ if (new_thread == previous_thread)
+ return;
+
+ Process* const previous_process = Core::CurrentProcess();
+
+ UpdateLastContextSwitchTime(previous_thread, previous_process);
+
+ // Save context for previous thread
+ if (previous_thread) {
+ cpu_core.SaveContext(previous_thread->GetContext());
+ // Save the TPIDR_EL0 system register in case it was modified.
+ previous_thread->SetTPIDR_EL0(cpu_core.GetTPIDR_EL0());
+
+ if (previous_thread->GetStatus() == ThreadStatus::Running) {
+ // This is only the case when a reschedule is triggered without the current thread
+ // yielding execution (i.e. an event triggered, system core time-sliced, etc)
+ previous_thread->SetStatus(ThreadStatus::Ready);
+ }
+ previous_thread->SetIsRunning(false);
}
// Load context of new thread
if (new_thread) {
+ ASSERT_MSG(new_thread->GetProcessorID() == this->id,
+ "Thread must be assigned to this core.");
ASSERT_MSG(new_thread->GetStatus() == ThreadStatus::Ready,
"Thread must be ready to become running.");
// Cancel any outstanding wakeup events for this thread
new_thread->CancelWakeupTimer();
-
current_thread = new_thread;
-
- ready_queue.remove(new_thread, new_thread->GetPriority());
new_thread->SetStatus(ThreadStatus::Running);
+ new_thread->SetIsRunning(true);
auto* const thread_owner_process = current_thread->GetOwnerProcess();
if (previous_process != thread_owner_process) {
@@ -116,7 +375,7 @@ void Scheduler::SwitchContext(Thread* new_thread) {
void Scheduler::UpdateLastContextSwitchTime(Thread* thread, Process* process) {
const u64 prev_switch_ticks = last_context_switch_time;
- const u64 most_recent_switch_ticks = system.CoreTiming().GetTicks();
+ const u64 most_recent_switch_ticks = Core::System::GetInstance().CoreTiming().GetTicks();
const u64 update_ticks = most_recent_switch_ticks - prev_switch_ticks;
if (thread != nullptr) {
@@ -130,124 +389,4 @@ void Scheduler::UpdateLastContextSwitchTime(Thread* thread, Process* process) {
last_context_switch_time = most_recent_switch_ticks;
}
-void Scheduler::Reschedule() {
- std::lock_guard lock{scheduler_mutex};
-
- Thread* cur = GetCurrentThread();
- Thread* next = PopNextReadyThread();
-
- if (cur && next) {
- LOG_TRACE(Kernel, "context switch {} -> {}", cur->GetObjectId(), next->GetObjectId());
- } else if (cur) {
- LOG_TRACE(Kernel, "context switch {} -> idle", cur->GetObjectId());
- } else if (next) {
- LOG_TRACE(Kernel, "context switch idle -> {}", next->GetObjectId());
- }
-
- SwitchContext(next);
-}
-
-void Scheduler::AddThread(SharedPtr<Thread> thread) {
- std::lock_guard lock{scheduler_mutex};
-
- thread_list.push_back(std::move(thread));
-}
-
-void Scheduler::RemoveThread(Thread* thread) {
- std::lock_guard lock{scheduler_mutex};
-
- thread_list.erase(std::remove(thread_list.begin(), thread_list.end(), thread),
- thread_list.end());
-}
-
-void Scheduler::ScheduleThread(Thread* thread, u32 priority) {
- std::lock_guard lock{scheduler_mutex};
-
- ASSERT(thread->GetStatus() == ThreadStatus::Ready);
- ready_queue.add(thread, priority);
-}
-
-void Scheduler::UnscheduleThread(Thread* thread, u32 priority) {
- std::lock_guard lock{scheduler_mutex};
-
- ASSERT(thread->GetStatus() == ThreadStatus::Ready);
- ready_queue.remove(thread, priority);
-}
-
-void Scheduler::SetThreadPriority(Thread* thread, u32 priority) {
- std::lock_guard lock{scheduler_mutex};
- if (thread->GetPriority() == priority) {
- return;
- }
-
- // If thread was ready, adjust queues
- if (thread->GetStatus() == ThreadStatus::Ready)
- ready_queue.adjust(thread, thread->GetPriority(), priority);
-}
-
-Thread* Scheduler::GetNextSuggestedThread(u32 core, u32 maximum_priority) const {
- std::lock_guard lock{scheduler_mutex};
-
- const u32 mask = 1U << core;
- for (auto* thread : ready_queue) {
- if ((thread->GetAffinityMask() & mask) != 0 && thread->GetPriority() < maximum_priority) {
- return thread;
- }
- }
- return nullptr;
-}
-
-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
diff --git a/src/core/hle/kernel/scheduler.h b/src/core/hle/kernel/scheduler.h
index b29bf7be85..50fa7376b4 100644
--- a/src/core/hle/kernel/scheduler.h
+++ b/src/core/hle/kernel/scheduler.h
@@ -20,124 +20,141 @@ namespace Kernel {
class Process;
-class Scheduler final {
+class GlobalScheduler final {
public:
- explicit Scheduler(Core::System& system, Core::ARM_Interface& cpu_core);
- ~Scheduler();
-
- /// Returns whether there are any threads that are ready to run.
- bool HaveReadyThreads() const;
-
- /// Reschedules to the next available thread (call after current thread is suspended)
- void Reschedule();
-
- /// Gets the current running thread
- Thread* GetCurrentThread() const;
-
- /// Gets the timestamp for the last context switch in ticks.
- u64 GetLastContextSwitchTicks() const;
+ static constexpr u32 NUM_CPU_CORES = 4;
+ GlobalScheduler() {
+ reselection_pending = false;
+ }
+ ~GlobalScheduler();
/// Adds a new thread to the scheduler
void AddThread(SharedPtr<Thread> thread);
/// Removes a thread from the scheduler
void RemoveThread(Thread* thread);
- /// Schedules a thread that has become "ready"
- void ScheduleThread(Thread* thread, u32 priority);
-
- /// Unschedules a thread that was already scheduled
- void UnscheduleThread(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, u32 minimum_priority) const;
-
- /**
- * YieldWithoutLoadBalancing -- analogous to normal yield on a system
- * Moves the thread to the end of the ready queue for its priority, and then reschedules the
- * system to the new head of the queue.
- *
- * Example (Single Core -- but can be extrapolated to multi):
- * ready_queue[prio=0]: ThreadA, ThreadB, ThreadC (->exec order->)
- * Currently Running: ThreadR
- *
- * ThreadR calls YieldWithoutLoadBalancing
- *
- * ThreadR is moved to the end of ready_queue[prio=0]:
- * ready_queue[prio=0]: ThreadA, ThreadB, ThreadC, ThreadR (->exec order->)
- * Currently Running: Nothing
- *
- * System is rescheduled (ThreadA is popped off of queue):
- * ready_queue[prio=0]: ThreadB, ThreadC, ThreadR (->exec order->)
- * Currently Running: ThreadA
- *
- * If the queue is empty at time of call, no yielding occurs. This does not cross between cores
- * or priorities at all.
- */
- void YieldWithoutLoadBalancing(Thread* thread);
-
- /**
- * YieldWithLoadBalancing -- yield but with better selection of the new running thread
- * Moves the current thread to the end of the ready queue for its priority, then selects a
- * 'suggested thread' (a thread on a different core that could run on this core) from the
- * scheduler, changes its core, and reschedules the current core to that thread.
- *
- * Example (Dual Core -- can be extrapolated to Quad Core, this is just normal yield if it were
- * single core):
- * ready_queue[core=0][prio=0]: ThreadA, ThreadB (affinities not pictured as irrelevant
- * ready_queue[core=1][prio=0]: ThreadC[affinity=both], ThreadD[affinity=core1only]
- * Currently Running: ThreadQ on Core 0 || ThreadP on Core 1
- *
- * ThreadQ calls YieldWithLoadBalancing
- *
- * ThreadQ is moved to the end of ready_queue[core=0][prio=0]:
- * ready_queue[core=0][prio=0]: ThreadA, ThreadB
- * ready_queue[core=1][prio=0]: ThreadC[affinity=both], ThreadD[affinity=core1only]
- * Currently Running: ThreadQ on Core 0 || ThreadP on Core 1
- *
- * A list of suggested threads for each core is compiled
- * Suggested Threads: {ThreadC on Core 1}
- * If this were quad core (as the switch is), there could be between 0 and 3 threads in this
- * list. If there are more than one, the thread is selected by highest prio.
- *
- * ThreadC is core changed to Core 0:
- * ready_queue[core=0][prio=0]: ThreadC, ThreadA, ThreadB, ThreadQ
- * ready_queue[core=1][prio=0]: ThreadD
- * Currently Running: None on Core 0 || ThreadP on Core 1
- *
- * System is rescheduled (ThreadC is popped off of queue):
- * ready_queue[core=0][prio=0]: ThreadA, ThreadB, ThreadQ
- * ready_queue[core=1][prio=0]: ThreadD
- * Currently Running: ThreadC on Core 0 || ThreadP on Core 1
- *
- * If no suggested threads can be found this will behave just as normal yield. If there are
- * multiple candidates for the suggested thread on a core, the highest prio is taken.
- */
- void YieldWithLoadBalancing(Thread* thread);
-
- /// Currently unknown -- asserts as unimplemented on call
- void YieldAndWaitForLoadBalancing(Thread* thread);
-
/// Returns a list of all threads managed by the scheduler
const std::vector<SharedPtr<Thread>>& GetThreadList() const {
return thread_list;
}
-private:
- /**
- * Pops and returns the next thread from the thread queue
- * @return A pointer to the next ready thread
- */
- Thread* PopNextReadyThread();
+ void Suggest(u32 priority, u32 core, Thread* thread) {
+ suggested_queue[core].add(thread, priority);
+ }
+ void Unsuggest(u32 priority, u32 core, Thread* thread) {
+ suggested_queue[core].remove(thread, priority);
+ }
+
+ void Schedule(u32 priority, u32 core, Thread* thread) {
+ ASSERT_MSG(thread->GetProcessorID() == core,
+ "Thread must be assigned to this core.");
+ scheduled_queue[core].add(thread, priority);
+ }
+
+ void SchedulePrepend(u32 priority, u32 core, Thread* thread) {
+ ASSERT_MSG(thread->GetProcessorID() == core,
+ "Thread must be assigned to this core.");
+ scheduled_queue[core].add(thread, priority, false);
+ }
+
+ void Reschedule(u32 priority, u32 core, Thread* thread) {
+ scheduled_queue[core].remove(thread, priority);
+ scheduled_queue[core].add(thread, priority);
+ }
+
+ void Unschedule(u32 priority, u32 core, Thread* thread) {
+ scheduled_queue[core].remove(thread, priority);
+ }
+
+ void TransferToCore(u32 priority, s32 destination_core, Thread* thread) {
+ bool schedulable = thread->GetPriority() < THREADPRIO_COUNT;
+ s32 source_core = thread->GetProcessorID();
+ if (source_core == destination_core || !schedulable)
+ return;
+ thread->SetProcessorID(destination_core);
+ if (source_core >= 0)
+ Unschedule(priority, source_core, thread);
+ if (destination_core >= 0) {
+ Unsuggest(priority, destination_core, thread);
+ Schedule(priority, destination_core, thread);
+ }
+ if (source_core >= 0)
+ Suggest(priority, source_core, thread);
+ }
+
+ void UnloadThread(s32 core);
+
+ void SelectThreads();
+ void SelectThread(u32 core);
+
+ bool HaveReadyThreads(u32 core_id) {
+ return !scheduled_queue[core_id].empty();
+ }
+
+ void YieldThread(Thread* thread);
+ void YieldThreadAndBalanceLoad(Thread* thread);
+ void YieldThreadAndWaitForLoadBalancing(Thread* thread);
+
+ u32 CpuCoresCount() const {
+ return NUM_CPU_CORES;
+ }
+
+ void SetReselectionPending() {
+ reselection_pending.store(true, std::memory_order_release);
+ }
+
+ bool IsReselectionPending() {
+ return reselection_pending.load(std::memory_order_acquire);
+ }
+
+private:
+ void AskForReselectionOrMarkRedundant(Thread* current_thread, Thread* winner);
+
+ static constexpr u32 min_regular_priority = 2;
+ std::array<Common::MultiLevelQueue<Thread*, THREADPRIO_COUNT>, NUM_CPU_CORES> scheduled_queue;
+ std::array<Common::MultiLevelQueue<Thread*, THREADPRIO_COUNT>, NUM_CPU_CORES> suggested_queue;
+ std::atomic<bool> reselection_pending;
+
+ /// Lists all thread ids that aren't deleted/etc.
+ std::vector<SharedPtr<Thread>> thread_list;
+};
+
+class Scheduler final {
+public:
+ explicit Scheduler(Core::System& system, Core::ARM_Interface& cpu_core, const u32 id);
+ ~Scheduler();
+
+ /// Returns whether there are any threads that are ready to run.
+ bool HaveReadyThreads() const;
+
+ /// Reschedules to the next available thread (call after current thread is suspended)
+ void TryDoContextSwitch();
+
+ void UnloadThread();
+
+ void SelectThreads();
+
+ /// Gets the current running thread
+ Thread* GetCurrentThread() const;
+
+ Thread* GetSelectedThread() const;
+
+ /// Gets the timestamp for the last context switch in ticks.
+ u64 GetLastContextSwitchTicks() const;
+
+ bool ContextSwitchPending() const {
+ return context_switch_pending;
+ }
+
+private:
+ friend class GlobalScheduler;
/**
* Switches the CPU's active thread context to that of the specified thread
* @param new_thread The thread to switch to
*/
- void SwitchContext(Thread* new_thread);
+ void SwitchContext();
/**
* Called on every context switch to update the internal timestamp
@@ -152,19 +169,16 @@ private:
*/
void UpdateLastContextSwitchTime(Thread* thread, Process* process);
- /// Lists all thread ids that aren't deleted/etc.
- std::vector<SharedPtr<Thread>> thread_list;
-
- /// Lists only ready thread ids.
- Common::MultiLevelQueue<Thread*, THREADPRIO_LOWEST + 1> ready_queue;
-
SharedPtr<Thread> current_thread = nullptr;
-
- Core::ARM_Interface& cpu_core;
- u64 last_context_switch_time = 0;
+ SharedPtr<Thread> selected_thread = nullptr;
Core::System& system;
- static std::mutex scheduler_mutex;
+ Core::ARM_Interface& cpu_core;
+ u64 last_context_switch_time = 0;
+ u64 idle_selection_count = 0;
+ const u32 id;
+
+ bool context_switch_pending = false;
};
} // namespace Kernel