Implement a new Core Scheduler
This commit is contained in:
Fernando Sahmkow
committed by
FernandoS27
FernandoS27
parent
cab2619aeb
commit
b164d8ee53
@@ -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
|
||||
|
||||
@@ -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
|
||||
|
||||
Reference in New Issue
Block a user