/* PCSX2 - PS2 Emulator for PCs
* Copyright (C) 2002-2010 PCSX2 Dev Team
*
* PCSX2 is free software: you can redistribute it and/or modify it under the terms
* of the GNU Lesser General Public License as published by the Free Software Found-
* ation, either version 3 of the License, or (at your option) any later version.
*
* PCSX2 is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
* PURPOSE. See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along with PCSX2.
* If not, see .
*/
#pragma once
#include "common/Pcsx2Defs.h"
#include "common/General.h"
#if defined(__APPLE__)
#include
#elif !defined(_WIN32)
#include
#endif
#include
// --------------------------------------------------------------------------------------
// PCSX2_THREAD_LOCAL - Defines platform/operating system support for Thread Local Storage
// --------------------------------------------------------------------------------------
//
// TLS is enabled by default. It will be disabled at compile time for Linux plugin.
// If you link SPU2X/ZZOGL with a TLS library, you will consume a DVT slots. Slots
// are rather limited and it ends up to "impossible to dlopen the library"
// None of the above plugin uses TLS variable in a multithread context
#ifndef PCSX2_THREAD_LOCAL
#define PCSX2_THREAD_LOCAL 1
#endif
#if PCSX2_THREAD_LOCAL
#define DeclareTls(x) thread_local x
#else
#define DeclareTls(x) x
#endif
namespace Threading
{
// --------------------------------------------------------------------------------------
// Platform Specific External APIs
// --------------------------------------------------------------------------------------
// The following set of documented functions have Linux/Win32 specific implementations,
// which are found in WinThreads.cpp and LnxThreads.cpp
extern u64 GetThreadCpuTime();
extern u64 GetThreadTicksPerSecond();
/// Set the name of the current thread
extern void SetNameOfCurrentThread(const char* name);
// Releases a timeslice to other threads.
extern void Timeslice();
// For use in spin/wait loops.
extern void SpinWait();
// Optional implementation to enable hires thread/process scheduler for the operating system.
// Needed by Windows, but might not be relevant to other platforms.
extern void EnableHiresScheduler();
extern void DisableHiresScheduler();
// sleeps the current thread for the given number of milliseconds.
extern void Sleep(int ms);
// --------------------------------------------------------------------------------------
// ThreadHandle
// --------------------------------------------------------------------------------------
// Abstracts an OS's handle to a thread, closing the handle when necessary. Currently,
// only used for getting the CPU time for a thread.
//
class ThreadHandle
{
public:
ThreadHandle();
ThreadHandle(ThreadHandle&& handle);
ThreadHandle(const ThreadHandle& handle);
~ThreadHandle();
/// Returns a new handle for the calling thread.
static ThreadHandle GetForCallingThread();
ThreadHandle& operator=(ThreadHandle&& handle);
ThreadHandle& operator=(const ThreadHandle& handle);
operator void*() const { return m_native_handle; }
operator bool() const { return (m_native_handle != nullptr); }
/// Returns the amount of CPU time consumed by the thread, at the GetThreadTicksPerSecond() frequency.
u64 GetCPUTime() const;
/// Sets the affinity for a thread to the specified processors.
/// Obviously, only works up to 64 processors.
bool SetAffinity(u64 processor_mask) const;
private:
void* m_native_handle = nullptr;
// We need the thread ID for affinity adjustments on Linux.
#if defined(__linux__)
unsigned int m_native_id = 0;
#endif
};
/// A semaphore that may not have a fast userspace path
/// (Used in other semaphore-based algorithms where the semaphore is just used for its thread sleep/wake ability)
class KernelSemaphore
{
#if defined(_WIN32)
void* m_sema;
#elif defined(__APPLE__)
semaphore_t m_sema;
#else
sem_t m_sema;
#endif
public:
KernelSemaphore();
~KernelSemaphore();
void Post();
void Wait();
bool TryWait();
};
/// A semaphore for notifying a work-processing thread of new work in a (separate) queue
///
/// Usage:
/// - Processing thread loops on `WaitForWork()` followed by processing all work in the queue
/// - Threads adding work first add their work to the queue, then call `NotifyOfWork()`
class WorkSema
{
/// Semaphore for sleeping the worker thread
KernelSemaphore m_sema;
/// Semaphore for sleeping thread waiting on worker queue empty
KernelSemaphore m_empty_sema;
/// Current state (see enum below)
std::atomic m_state{0};
// Expected call frequency is NotifyOfWork > WaitForWork > WaitForEmpty
// So optimize states for fast NotifyOfWork
enum
{
/* Any <-2 state: STATE_DEAD: Thread has crashed and is awaiting revival */
STATE_SPINNING = -2, ///< Worker thread is spinning waiting for work
STATE_SLEEPING = -1, ///< Worker thread is sleeping on m_sema
STATE_RUNNING_0 = 0, ///< Worker thread is processing work, but no work has been added since it last checked for new work
/* Any >0 state: STATE_RUNNING_N: Worker thread is processing work, and work has been added since it last checked for new work */
STATE_FLAG_WAITING_EMPTY = 1 << 30, ///< Flag to indicate that a thread is sleeping on m_empty_sema (can be applied to any STATE_RUNNING)
};
bool IsDead(s32 state)
{
return state < STATE_SPINNING;
}
bool IsReadyForSleep(s32 state)
{
s32 waiting_empty_cleared = state & (STATE_FLAG_WAITING_EMPTY - 1);
return waiting_empty_cleared == STATE_RUNNING_0;
}
s32 NextStateWaitForWork(s32 current)
{
s32 new_state = IsReadyForSleep(current) ? STATE_SLEEPING : STATE_RUNNING_0;
return new_state | (current & STATE_FLAG_WAITING_EMPTY); // Preserve waiting empty flag for RUNNING_N → RUNNING_0
}
public:
/// Notify the worker thread that you've added new work to its queue
void NotifyOfWork()
{
// State change:
// DEAD: Stay in DEAD (starting DEAD state is INT_MIN so we can assume we won't flip over to anything else)
// SPINNING: Change state to RUNNING. Thread will notice and process the new data
// SLEEPING: Change state to RUNNING and wake worker. Thread will wake up and process the new data.
// RUNNING_0: Change state to RUNNING_N.
// RUNNING_N: Stay in RUNNING_N
s32 old = m_state.fetch_add(2, std::memory_order_release);
if (old == STATE_SLEEPING)
m_sema.Post();
}
/// Wait for work to be added to the queue
void WaitForWork();
/// Wait for work to be added to the queue, spinning for a bit before sleeping the thread
void WaitForWorkWithSpin();
/// Wait for the worker thread to finish processing all entries in the queue or die
/// Returns false if the thread is dead
bool WaitForEmpty();
/// Wait for the worker thread to finish processing all entries in the queue or die, spinning a bit before sleeping the thread
/// Returns false if the thread is dead
bool WaitForEmptyWithSpin();
/// Called by the worker thread to notify others of its death
/// Dead threads don't process work, and WaitForEmpty will return instantly even though there may be work in the queue
void Kill();
/// Reset the semaphore to the initial state
/// Should be called by the worker thread if it restarts after dying
void Reset();
};
} // namespace Threading