Implement a new Core Scheduler

This commit is contained in:
Fernando Sahmkow 2019-03-29 17:01:17 -04:00 committed by FernandoS27
parent cab2619aeb
commit b164d8ee53
2 changed files with 421 additions and 268 deletions

View file

@ -3,6 +3,8 @@
// Refer to the license.txt file included. // Refer to the license.txt file included.
#include <algorithm> #include <algorithm>
#include <set>
#include <unordered_set>
#include <utility> #include <utility>
#include "common/assert.h" #include "common/assert.h"
@ -17,57 +19,286 @@
namespace Kernel { 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) void GlobalScheduler::RemoveThread(Thread* thread) {
: cpu_core{cpu_core}, system{system} {} thread_list.erase(std::remove(thread_list.begin(), thread_list.end(), thread),
thread_list.end());
}
Scheduler::~Scheduler() { /*
for (auto& thread : thread_list) { * SelectThreads, Yield functions originally by TuxSH.
thread->Stop(); * 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 { bool Scheduler::HaveReadyThreads() const {
std::lock_guard lock{scheduler_mutex}; return system.GlobalScheduler().HaveReadyThreads(id);
return !ready_queue.empty();
} }
Thread* Scheduler::GetCurrentThread() const { Thread* Scheduler::GetCurrentThread() const {
return current_thread.get(); return current_thread.get();
} }
Thread* Scheduler::GetSelectedThread() const {
return selected_thread.get();
}
void Scheduler::SelectThreads() {
system.GlobalScheduler().SelectThread(id);
}
u64 Scheduler::GetLastContextSwitchTicks() const { u64 Scheduler::GetLastContextSwitchTicks() const {
return last_context_switch_time; return last_context_switch_time;
} }
Thread* Scheduler::PopNextReadyThread() { void Scheduler::TryDoContextSwitch() {
Thread* next = nullptr; if (context_switch_pending)
Thread* thread = GetCurrentThread(); SwitchContext();
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::UnloadThread() {
} Thread* const previous_thread = GetCurrentThread();
Process* const previous_process = Core::CurrentProcess();
void Scheduler::SwitchContext(Thread* new_thread) {
Thread* previous_thread = GetCurrentThread();
Process* const previous_process = system.Kernel().CurrentProcess();
UpdateLastContextSwitchTime(previous_thread, previous_process); UpdateLastContextSwitchTime(previous_thread, previous_process);
@ -80,23 +311,51 @@ void Scheduler::SwitchContext(Thread* new_thread) {
if (previous_thread->GetStatus() == ThreadStatus::Running) { if (previous_thread->GetStatus() == ThreadStatus::Running) {
// This is only the case when a reschedule is triggered without the current thread // 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) // 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->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 // Load context of new thread
if (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, ASSERT_MSG(new_thread->GetStatus() == ThreadStatus::Ready,
"Thread must be ready to become running."); "Thread must be ready to become running.");
// Cancel any outstanding wakeup events for this thread // Cancel any outstanding wakeup events for this thread
new_thread->CancelWakeupTimer(); new_thread->CancelWakeupTimer();
current_thread = new_thread; current_thread = new_thread;
ready_queue.remove(new_thread, new_thread->GetPriority());
new_thread->SetStatus(ThreadStatus::Running); new_thread->SetStatus(ThreadStatus::Running);
new_thread->SetIsRunning(true);
auto* const thread_owner_process = current_thread->GetOwnerProcess(); auto* const thread_owner_process = current_thread->GetOwnerProcess();
if (previous_process != thread_owner_process) { if (previous_process != thread_owner_process) {
@ -116,7 +375,7 @@ void Scheduler::SwitchContext(Thread* new_thread) {
void Scheduler::UpdateLastContextSwitchTime(Thread* thread, Process* process) { void Scheduler::UpdateLastContextSwitchTime(Thread* thread, Process* process) {
const u64 prev_switch_ticks = last_context_switch_time; 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; const u64 update_ticks = most_recent_switch_ticks - prev_switch_ticks;
if (thread != nullptr) { if (thread != nullptr) {
@ -130,124 +389,4 @@ void Scheduler::UpdateLastContextSwitchTime(Thread* thread, Process* process) {
last_context_switch_time = most_recent_switch_ticks; 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 } // namespace Kernel

View file

@ -20,124 +20,141 @@ namespace Kernel {
class Process; class Process;
class Scheduler final { class GlobalScheduler final {
public: public:
explicit Scheduler(Core::System& system, Core::ARM_Interface& cpu_core); static constexpr u32 NUM_CPU_CORES = 4;
~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;
GlobalScheduler() {
reselection_pending = false;
}
~GlobalScheduler();
/// Adds a new thread to the scheduler /// Adds a new thread to the scheduler
void AddThread(SharedPtr<Thread> thread); void AddThread(SharedPtr<Thread> thread);
/// Removes a thread from the scheduler /// Removes a thread from the scheduler
void RemoveThread(Thread* thread); 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 /// Returns a list of all threads managed by the scheduler
const std::vector<SharedPtr<Thread>>& GetThreadList() const { const std::vector<SharedPtr<Thread>>& GetThreadList() const {
return thread_list; return thread_list;
} }
private: void Suggest(u32 priority, u32 core, Thread* thread) {
/** suggested_queue[core].add(thread, priority);
* Pops and returns the next thread from the thread queue }
* @return A pointer to the next ready thread
*/
Thread* PopNextReadyThread();
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 * Switches the CPU's active thread context to that of the specified thread
* @param new_thread The thread to switch to * @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 * Called on every context switch to update the internal timestamp
@ -152,19 +169,16 @@ private:
*/ */
void UpdateLastContextSwitchTime(Thread* thread, Process* process); 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; SharedPtr<Thread> current_thread = nullptr;
SharedPtr<Thread> selected_thread = nullptr;
Core::ARM_Interface& cpu_core;
u64 last_context_switch_time = 0;
Core::System& system; 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 } // namespace Kernel