pcsx2/pcsx2/Threading.h

281 lines
9.0 KiB
C++

/* Pcsx2 - Pc Ps2 Emulator
* Copyright (C) 2002-2009 Pcsx2 Team
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
*/
#ifndef _THREADING_H_
#define _THREADING_H_
#include <errno.h> // EBUSY
#include <semaphore.h>
#include "PS2Etypes.h"
#include "Exceptions.h"
namespace Threading
{
///////////////////////////////////////////////////////////////
// Define some useful object handles - wait events, mutexes.
struct WaitEvent
{
pthread_cond_t cond;
pthread_mutex_t mutex;
WaitEvent();
~WaitEvent();
void Set();
void Wait();
};
struct Semaphore
{
sem_t sema;
Semaphore();
~Semaphore();
void Reset();
void Post();
void Post( int multiple );
void Wait();
int Count();
};
struct MutexLock
{
pthread_mutex_t mutex;
MutexLock();
~MutexLock();
void Lock();
void Unlock();
};
// Returns the number of available logical CPUs (cores plus hyperthreaded cpus)
extern void CountLogicalCores( int LogicalCoresPerPhysicalCPU, int PhysicalCoresPerPhysicalCPU );
// Releases a timeslice to other threads.
extern void Timeslice();
// For use in spin/wait loops.
extern void SpinWait();
// sleeps the current thread for the given number of milliseconds.
extern void Sleep( int ms );
//////////////////////////////////////////////////////////////////////////////////////////
// Thread - Helper class for the basics of starting/managing simple threads.
//
// Use this as a base class for your threaded procedure, and implement the 'int Callback()'
// method. Use Start() and Close() to start and shutdown the thread, and use m_post_event
// internally to post/receive events for the thread (make a public accessor for it in your
// derived class if your thread utilizes the post).
//
// Notes:
// * To ensure thread safety against C++'s bizarre and not-thread-friendly object
// constructors and destructors, you *must* use Start() and Close(). There is a built-
// in Close() called on destruction, which should work for very simple threads (that
// do not have any special shutdown code of their own), but
//
// * Constructing threads as static vars isn't recommended since it can potentially con-
// fuse w32pthreads, if the static initializers are executed out-of-order (C++ offers
// no dependency options for ensuring correct static var initializations).
//
class Thread : NoncopyableObject
{
protected:
typedef int (*PlainJoeFP)();
pthread_t m_thread;
int m_returncode; // value returned from the thread on close.
bool m_terminated; // set true after the thread has been closed.
Semaphore m_post_event; // general wait event that's needed by most threads.
public:
virtual ~Thread();
Thread();
virtual void Start();
virtual void Close();
// Gets the return code of the thread.
// Throws std::logic_error if the thread has not terminated.
int GetReturnCode() const;
protected:
// Used to dispatch the thread callback function.
// (handles some thread cleanup on Win32, and is basically a typecast
// on linux).
static void* _internal_callback( void* func );
// Implemented by derived class to handle threading actions!
virtual int Callback()=0;
};
//////////////////////////////////////////////////////////////////////////////////////////
// ScopedLock: Helper class for using Mutexes.
// Using this class provides an exception-safe (and generally clean) method of locking
// code inside a function or conditional block.
//
class ScopedLock : NoncopyableObject
{
protected:
MutexLock& m_lock;
public:
virtual ~ScopedLock()
{
m_lock.Unlock();
}
ScopedLock( MutexLock& locker ) :
m_lock( locker )
{
m_lock.Lock();
}
};
//////////////////////////////////////////////////////////////////////////////////////////
// BaseTaskThread - an abstract base class which provides simple parallel execution of
// single tasks.
//
// Implementation:
// To use this class your derived class will need to implement its own Task() function
// and also a "StartTask( parameters )" function which suits the need of your task, along
// with any local variables your task needs to do its job. You may additionally want to
// implement a "GetResult()" function, which would be a combination of WaitForResult()
// and a return value of the computational result.
//
// Thread Safety:
// If operating on local variables, you must execute WaitForResult() before leaving the
// variable scope -- or alternatively have your StartTask() implementation make full
// copies of dependent data. Also, by default PostTask() always assumes the previous
// task has completed. If your system can post a new task before the previous one has
// completed, then it needs to explicitly call WaitForResult() or provide a mechanism
// to cancel the previous task (which is probably more work than it's worth).
//
// Performance notes:
// * Remember that thread creation is generally slow, so you should make your object
// instance once early and then feed it tasks repeatedly over the course of program
// execution.
//
// * For threading to be a successful speedup, the task being performed should be as lock
// free as possible. For example using STL containers in parallel usually fails to
// yield any speedup due to the gratuitous amount of locking that the STL performs
// internally.
//
// * The best application of tasking threads is to divide a large loop over a linear array
// into smaller sections. For example, if you have 20,000 items to process, the task
// can be divided into two threads of 10,000 items each.
//
class BaseTaskThread : public Thread
{
protected:
volatile bool m_done;
volatile bool m_TaskComplete;
public:
virtual ~BaseTaskThread() {}
BaseTaskThread() :
m_done( false )
, m_TaskComplete( false )
{
}
// Tells the thread to exit and then waits for thread termination.
// To force-terminate the thread without "nicely" waiting for the task to complete,
// explicitly use the Thread::Close parent implementation instead.
void Close()
{
if( m_terminated ) return;
m_done = true;
m_post_event.Post();
pthread_join( m_thread, NULL );
}
// Initiates the new task. This should be called after your own StartTask has
// initialized internal variables / preparations for task execution.
void PostTask()
{
jASSUME( !m_terminated );
m_TaskComplete = false;
m_post_event.Post();
}
// Blocks current thread execution pending the completion of the parallel task.
void WaitForResult() const
{
if( m_terminated ) return;
while( !m_TaskComplete )
{
Timeslice();
SpinWait();
}
}
protected:
// Abstract method run when a task has been posted. Implementing classes should do
// all your necessary processing work here.
virtual void Task()=0;
int Callback()
{
do
{
// Wait for a job!
m_post_event.Wait();
if( m_done ) break;
Task();
m_TaskComplete = true;
} while( !m_done );
return 0;
}
};
//////////////////////////////////////////////////////////////////////////////////////////
// Our fundamental interlocking functions. All other useful interlocks can be derived
// from these little beasties!
extern long pcsx2_InterlockedExchange(volatile long* Target, long srcval);
extern long pcsx2_InterlockedCompareExchange( volatile long* target, long srcval, long comp );
extern long pcsx2_InterlockedExchangeAdd( volatile long* target, long addval );
extern void AtomicExchange( volatile u32& Target, u32 value );
extern void AtomicExchangeAdd( volatile u32& Target, u32 value );
extern void AtomicIncrement( volatile u32& Target );
extern void AtomicDecrement( volatile u32& Target );
extern void AtomicExchange( volatile s32& Target, s32 value );
extern void AtomicExchangeAdd( volatile s32& Target, u32 value );
extern void AtomicIncrement( volatile s32& Target );
extern void AtomicDecrement( volatile s32& Target );
extern void _AtomicExchangePointer( const void ** target, const void* value );
extern void _AtomicCompareExchangePointer( const void ** target, const void* value, const void* comparand );
#define AtomicExchangePointer( target, value ) \
_AtomicExchangePointer( (const void**)(&target), (const void*)(value) )
#define AtomicCompareExchangePointer( target, value, comparand ) \
_AtomicCompareExchangePointer( (const void**)(&target), (const void*)(value), (const void*)(comparand) )
}
#endif