6c8f28813c
This is only compared against, so it can be made const.
228 lines
7.3 KiB
C++
228 lines
7.3 KiB
C++
// Copyright 2018 yuzu emulator team
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// Licensed under GPLv2 or any later version
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// Refer to the license.txt file included.
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#pragma once
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#include <mutex>
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#include <vector>
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#include "common/common_types.h"
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#include "common/multi_level_queue.h"
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#include "core/hle/kernel/object.h"
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#include "core/hle/kernel/thread.h"
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namespace Core {
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class ARM_Interface;
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class System;
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} // namespace Core
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namespace Kernel {
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class Process;
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class GlobalScheduler final {
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public:
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static constexpr u32 NUM_CPU_CORES = 4;
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explicit GlobalScheduler(Core::System& system);
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~GlobalScheduler();
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/// Adds a new thread to the scheduler
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void AddThread(SharedPtr<Thread> thread);
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/// Removes a thread from the scheduler
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void RemoveThread(const Thread* thread);
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/// Returns a list of all threads managed by the scheduler
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const std::vector<SharedPtr<Thread>>& GetThreadList() const {
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return thread_list;
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}
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/**
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* Add a thread to the suggested queue of a cpu core. Suggested threads may be
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* picked if no thread is scheduled to run on the core.
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*/
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void Suggest(u32 priority, u32 core, Thread* thread);
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/**
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* Remove a thread to the suggested queue of a cpu core. Suggested threads may be
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* picked if no thread is scheduled to run on the core.
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*/
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void Unsuggest(u32 priority, u32 core, Thread* thread);
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/**
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* Add a thread to the scheduling queue of a cpu core. The thread is added at the
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* back the queue in its priority level.
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*/
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void Schedule(u32 priority, u32 core, Thread* thread);
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/**
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* Add a thread to the scheduling queue of a cpu core. The thread is added at the
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* front the queue in its priority level.
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*/
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void SchedulePrepend(u32 priority, u32 core, Thread* thread);
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/// Reschedule an already scheduled thread based on a new priority
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void Reschedule(u32 priority, u32 core, Thread* thread);
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/// Unschedules a thread.
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void Unschedule(u32 priority, u32 core, Thread* thread);
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/**
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* Transfers a thread into an specific core. If the destination_core is -1
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* it will be unscheduled from its source code and added into its suggested
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* queue.
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*/
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void TransferToCore(u32 priority, s32 destination_core, Thread* thread);
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/// Selects a core and forces it to unload its current thread's context
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void UnloadThread(s32 core);
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/**
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* Takes care of selecting the new scheduled thread in three steps:
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*
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* 1. First a thread is selected from the top of the priority queue. If no thread
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* is obtained then we move to step two, else we are done.
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*
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* 2. Second we try to get a suggested thread that's not assigned to any core or
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* that is not the top thread in that core.
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*
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* 3. Third is no suggested thread is found, we do a second pass and pick a running
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* thread in another core and swap it with its current thread.
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*/
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void SelectThread(u32 core);
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bool HaveReadyThreads(u32 core_id) const {
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return !scheduled_queue[core_id].empty();
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}
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/**
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* Takes a thread and moves it to the back of the it's priority list.
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*
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* @note This operation can be redundant and no scheduling is changed if marked as so.
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*/
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bool YieldThread(Thread* thread);
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/**
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* Takes a thread and moves it to the back of the it's priority list.
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* Afterwards, tries to pick a suggested thread from the suggested queue that has worse time or
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* a better priority than the next thread in the core.
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*
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* @note This operation can be redundant and no scheduling is changed if marked as so.
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*/
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bool YieldThreadAndBalanceLoad(Thread* thread);
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/**
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* Takes a thread and moves it out of the scheduling queue.
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* and into the suggested queue. If no thread can be scheduled afterwards in that core,
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* a suggested thread is obtained instead.
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*
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* @note This operation can be redundant and no scheduling is changed if marked as so.
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*/
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bool YieldThreadAndWaitForLoadBalancing(Thread* thread);
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/**
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* Rotates the scheduling queues of threads at a preemption priority and then does
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* some core rebalancing. Preemption priorities can be found in the array
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* 'preemption_priorities'.
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*
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* @note This operation happens every 10ms.
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*/
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void PreemptThreads();
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u32 CpuCoresCount() const {
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return NUM_CPU_CORES;
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}
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void SetReselectionPending() {
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is_reselection_pending.store(true, std::memory_order_release);
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}
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bool IsReselectionPending() const {
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return is_reselection_pending.load(std::memory_order_acquire);
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}
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void Shutdown();
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private:
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bool AskForReselectionOrMarkRedundant(Thread* current_thread, const Thread* winner);
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static constexpr u32 min_regular_priority = 2;
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std::array<Common::MultiLevelQueue<Thread*, THREADPRIO_COUNT>, NUM_CPU_CORES> scheduled_queue;
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std::array<Common::MultiLevelQueue<Thread*, THREADPRIO_COUNT>, NUM_CPU_CORES> suggested_queue;
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std::atomic<bool> is_reselection_pending{false};
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// The priority levels at which the global scheduler preempts threads every 10 ms. They are
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// ordered from Core 0 to Core 3.
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std::array<u32, NUM_CPU_CORES> preemption_priorities = {59, 59, 59, 62};
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/// Lists all thread ids that aren't deleted/etc.
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std::vector<SharedPtr<Thread>> thread_list;
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Core::System& system;
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};
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class Scheduler final {
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public:
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explicit Scheduler(Core::System& system, Core::ARM_Interface& cpu_core, u32 core_id);
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~Scheduler();
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/// Returns whether there are any threads that are ready to run.
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bool HaveReadyThreads() const;
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/// Reschedules to the next available thread (call after current thread is suspended)
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void TryDoContextSwitch();
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/// Unloads currently running thread
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void UnloadThread();
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/// Select the threads in top of the scheduling multilist.
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void SelectThreads();
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/// Gets the current running thread
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Thread* GetCurrentThread() const;
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/// Gets the currently selected thread from the top of the multilevel queue
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Thread* GetSelectedThread() const;
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/// Gets the timestamp for the last context switch in ticks.
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u64 GetLastContextSwitchTicks() const;
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bool ContextSwitchPending() const {
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return is_context_switch_pending;
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}
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/// Shutdowns the scheduler.
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void Shutdown();
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private:
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friend class GlobalScheduler;
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/// Switches the CPU's active thread context to that of the specified thread
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void SwitchContext();
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/**
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* Called on every context switch to update the internal timestamp
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* This also updates the running time ticks for the given thread and
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* process using the following difference:
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*
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* ticks += most_recent_ticks - last_context_switch_ticks
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*
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* The internal tick timestamp for the scheduler is simply the
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* most recent tick count retrieved. No special arithmetic is
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* applied to it.
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*/
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void UpdateLastContextSwitchTime(Thread* thread, Process* process);
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SharedPtr<Thread> current_thread = nullptr;
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SharedPtr<Thread> selected_thread = nullptr;
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Core::System& system;
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Core::ARM_Interface& cpu_core;
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u64 last_context_switch_time = 0;
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u64 idle_selection_count = 0;
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const u32 core_id;
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bool is_context_switch_pending = false;
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};
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} // namespace Kernel
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