suyu/src/core/hle/kernel/scheduler.h
Lioncash fad20213e6 kernel/scheduler: Pass in system instance in constructor
Avoids directly relying on the global system instance and instead makes
an arbitrary system instance an explicit dependency on construction.

This also allows removing dependencies on some global accessor functions
as well.
2019-03-04 17:01:37 -05:00

170 lines
6.1 KiB
C++

// Copyright 2018 yuzu emulator team
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#pragma once
#include <mutex>
#include <vector>
#include "common/common_types.h"
#include "common/thread_queue_list.h"
#include "core/hle/kernel/object.h"
#include "core/hle/kernel/thread.h"
namespace Core {
class ARM_Interface;
class System;
} // namespace Core
namespace Kernel {
class Process;
class Scheduler 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;
/// Adds a new thread to the scheduler
void AddThread(SharedPtr<Thread> thread, u32 priority);
/// 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();
/**
* 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);
/**
* Called on every context switch to update the internal timestamp
* This also updates the running time ticks for the given thread and
* process using the following difference:
*
* ticks += most_recent_ticks - last_context_switch_ticks
*
* The internal tick timestamp for the scheduler is simply the
* most recent tick count retrieved. No special arithmetic is
* applied to it.
*/
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::ThreadQueueList<Thread*, THREADPRIO_LOWEST + 1> ready_queue;
SharedPtr<Thread> current_thread = nullptr;
Core::ARM_Interface& cpu_core;
u64 last_context_switch_time = 0;
Core::System& system;
static std::mutex scheduler_mutex;
};
} // namespace Kernel