pcsx2/common/include/Utilities/Threading.h

480 lines
16 KiB
C++

/* PCSX2 - PS2 Emulator for PCs
* Copyright (C) 2002-2009 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 <http://www.gnu.org/licenses/>.
*/
#pragma once
#include <semaphore.h>
#include <errno.h> // EBUSY
#include <pthread.h>
#include "Pcsx2Defs.h"
#include "ScopedPtr.h"
#undef Yield // release th burden of windows.h global namespace spam.
class wxTimeSpan;
#define AllowFromMainThreadOnly() \
pxAssertMsg( wxThread::IsMain(), "Thread affinity violation: Call allowed from main thread only." )
namespace Exception
{
class ThreadCreationError : public virtual RuntimeError
{
public:
DEFINE_RUNTIME_EXCEPTION( ThreadCreationError, wxLt("Thread could not be created.") );
};
#if wxUSE_GUI
// --------------------------------------------------------------------------------------
// ThreadTimedOut Exception
// --------------------------------------------------------------------------------------
// This exception is thrown by Semaphore and Mutex Wait/Lock functions if a blocking wait is
// needed due to gui Yield recursion, and the timeout period for deadlocking (usually 3 seconds)
// is reached before the lock becomes available. This exception cannot occur in the following
// conditions:
// * If the user-specified timeout is less than the deadlock timeout.
// * If the method is run from a thread *other* than the MainGui thread.
class ThreadTimedOut : public virtual RuntimeError
{
public:
DEFINE_RUNTIME_EXCEPTION( ThreadTimedOut, "Blocking action timed out due to potential deadlock." );
};
#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
// 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();
// 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 );
// pthread Cond is an evil api that is not suited for Pcsx2 needs.
// Let's not use it. Use mutexes and semaphores instead to create waits. (Air)
#if 0
struct WaitEvent
{
pthread_cond_t cond;
pthread_mutex_t mutex;
WaitEvent();
~WaitEvent() throw();
void Set();
void Wait();
};
#endif
// --------------------------------------------------------------------------------------
// NonblockingMutex
// --------------------------------------------------------------------------------------
// This is a very simple non-blocking mutex, which behaves similarly to pthread_mutex's
// trylock(), but without any of the extra overhead needed to set up a structure capable
// of blocking waits. It basically optimizes to a single InterlockedExchange.
//
// Simple use: if TryLock() returns false, the Bool is already interlocked by another thread.
// If TryLock() returns true, you've locked the object and are *responsible* for unlocking
// it later.
//
class NonblockingMutex
{
protected:
volatile long val;
public:
NonblockingMutex() : val( false ) {}
virtual ~NonblockingMutex() throw() {}
bool TryLock() throw()
{
return !_InterlockedExchange( &val, true );
}
bool IsLocked()
{ return !!val; }
void Release()
{ val = false; }
};
class Semaphore
{
protected:
sem_t m_sema;
public:
Semaphore();
virtual ~Semaphore() throw();
void Reset();
void Post();
void Post( int multiple );
void WaitRaw();
bool WaitRaw( const wxTimeSpan& timeout );
void WaitNoCancel();
int Count();
void Wait();
bool Wait( const wxTimeSpan& timeout );
};
class MutexLock
{
protected:
pthread_mutex_t m_mutex;
public:
MutexLock();
virtual ~MutexLock() throw();
virtual bool IsRecursive() const { return false; }
void Recreate();
bool RecreateIfLocked();
void Detach();
void Lock();
bool Lock( const wxTimeSpan& timeout );
bool TryLock();
void Unlock();
void LockRaw();
bool LockRaw( const wxTimeSpan& timeout );
void Wait();
bool Wait( const wxTimeSpan& timeout );
protected:
// empty constructor used by MutexLockRecursive
MutexLock( bool ) {}
};
class MutexLockRecursive : public MutexLock
{
public:
MutexLockRecursive();
virtual ~MutexLockRecursive() throw();
virtual bool IsRecursive() const { return true; }
};
// --------------------------------------------------------------------------------------
// IThread - Interface for the public access to PersistentThread.
// --------------------------------------------------------------------------------------
// Class usage: Can be used for allowing safe nullification of a thread handle. Rather
// than being NULL'd, the handle can be mapped to an IThread implementation which acts
// as a do-nothing placebo or an assertion generator.
//
class IThread
{
DeclareNoncopyableObject(IThread);
public:
IThread() {}
virtual ~IThread() throw() {}
virtual bool IsSelf() const { return false; }
virtual bool IsRunning() { return false; }
virtual void Start() {}
virtual void Cancel( bool isBlocking = true ) {}
virtual void Block() {}
virtual bool Detach() { return false; }
};
// --------------------------------------------------------------------------------------
// PersistentThread - Helper class for the basics of starting/managing persistent threads.
// --------------------------------------------------------------------------------------
// This class is meant to be a helper for the typical threading model of "start once and
// reuse many times." This class incorporates a lot of extra overhead in stopping and
// starting threads, but in turn provides most of the basic thread-safety and event-handling
// functionality needed for a threaded operation. In practice this model is usually an
// ideal one for efficiency since Operating Systems themselves typically subscribe to a
// design where sleeping, suspending, and resuming threads is very efficient, but starting
// new threads has quite a bit of overhead.
//
// To use this as a base class for your threaded procedure, overload the following virtual
// methods:
// void OnStart();
// void ExecuteTaskInThread();
// void OnCleanupInThread();
//
// Use the public methods Start() and Cancel() to start and shutdown the thread, and use
// m_sem_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:
// * Constructing threads as static global vars isn't recommended since it can potentially
// confuse w32pthreads, if the static initializers are executed out-of-order (C++ offers
// no dependency options for ensuring correct static var initializations). Use heap
// allocation to create thread objects instead.
//
class PersistentThread : public virtual IThread
{
DeclareNoncopyableObject(PersistentThread);
protected:
typedef int (*PlainJoeFP)();
wxString m_name; // diagnostic name for our thread.
pthread_t m_thread;
Semaphore m_sem_event; // general wait event that's needed by most threads.
MutexLock m_lock_InThread; // used for canceling and closing threads in a deadlock-safe manner
MutexLockRecursive m_lock_start; // used to lock the Start() code from starting simultaneous threads accidentally.
volatile long m_detached; // a boolean value which indicates if the m_thread handle is valid
volatile long m_running; // set true by Start(), and set false by Cancel(), Block(), etc.
// exception handle, set non-NULL if the thread terminated with an exception
// Use RethrowException() to re-throw the exception using its original exception type.
ScopedPtr<Exception::BaseException> m_except;
public:
virtual ~PersistentThread() throw();
PersistentThread();
PersistentThread( const char* name );
virtual void Start();
virtual void Cancel( bool isBlocking = true );
virtual bool Detach();
virtual void Block();
virtual void RethrowException() const;
void WaitOnSelf( Semaphore& mutex );
void WaitOnSelf( MutexLock& mutex );
bool IsRunning() const;
bool IsSelf() const;
wxString GetName() const;
protected:
// Extending classes should always implement your own OnStart(), which is called by
// Start() once necessary locks have been obtained. Do not override Start() directly
// unless you're really sure that's what you need to do. ;)
virtual void OnStart();
virtual void OnStartInThread();
// This is called when the thread has been canceled or exits normally. The PersistentThread
// automatically binds it to the pthread cleanup routines as soon as the thread starts.
virtual void OnCleanupInThread();
// Implemented by derived class to perform actual threaded task!
virtual void ExecuteTaskInThread()=0;
void TestCancel();
// Yields this thread to other threads and checks for cancellation. A sleeping thread should
// always test for cancellation, however if you really don't want to, you can use Threading::Sleep()
// or better yet, disable cancellation of the thread completely with DisableCancellation().
//
// Parameters:
// ms - 'minimum' yield time in milliseconds (rough -- typically yields are longer by 1-5ms
// depending on operating system/platform). If ms is 0 or unspecified, then a single
// timeslice is yielded to other contending threads. If no threads are contending for
// time when ms==0, then no yield is done, but cancellation is still tested.
void Yield( int ms = 0 )
{
pxAssert( IsSelf() );
Threading::Sleep( ms );
TestCancel();
}
void FrankenMutex( MutexLock& mutex );
// ----------------------------------------------------------------------------
// Section of methods for internal use only.
void _DoSetThreadName( const wxString& name );
void _DoSetThreadName( const char* name );
void _internal_execute();
void _try_virtual_invoke( void (PersistentThread::*method)() );
void _ThreadCleanup();
static void* _internal_callback( void* func );
static void _pt_callback_cleanup( void* handle );
};
//////////////////////////////////////////////////////////////////////////////////////////
// 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
{
DeclareNoncopyableObject(ScopedLock);
protected:
MutexLock& m_lock;
bool m_IsLocked;
public:
virtual ~ScopedLock() throw()
{
if( m_IsLocked )
m_lock.Unlock();
}
ScopedLock( MutexLock& locker ) :
m_lock( locker )
, m_IsLocked( true )
{
m_lock.Lock();
}
// Provides manual unlocking of a scoped lock prior to object destruction.
void Unlock()
{
if( !m_IsLocked ) return;
m_IsLocked = false;
m_lock.Unlock();
}
// provides manual locking of a scoped lock, to re-lock after a manual unlocking.
void Lock()
{
if( m_IsLocked ) return;
m_lock.Lock();
m_IsLocked = true;
}
bool IsLocked() const { return m_IsLocked; }
protected:
// Special constructor used by ScopedTryLock
ScopedLock( MutexLock& locker, bool isTryLock ) :
m_lock( locker )
, m_IsLocked( isTryLock ? m_lock.TryLock() : false )
{
}
};
class ScopedTryLock : public ScopedLock
{
public:
ScopedTryLock( MutexLock& locker ) : ScopedLock( locker, true ) { }
virtual ~ScopedTryLock() throw() {}
bool Failed() const { return !m_IsLocked; }
};
//////////////////////////////////////////////////////////////////////////////////////////
// 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 PersistentThread
{
protected:
volatile bool m_Done;
volatile bool m_TaskPending;
Semaphore m_post_TaskComplete;
MutexLock m_lock_TaskComplete;
public:
virtual ~BaseTaskThread() throw() {}
BaseTaskThread() :
m_Done( false )
, m_TaskPending( false )
, m_post_TaskComplete()
{
}
void Block();
void PostTask();
void WaitForResult();
protected:
// Abstract method run when a task has been posted. Implementing classes should do
// all your necessary processing work here.
virtual void Task()=0;
virtual void ExecuteTaskInThread();
};
//////////////////////////////////////////////////////////////////////////////////////////
// Our fundamental interlocking functions. All other useful interlocks can be derived
// from these little beasties!
extern u32 AtomicExchange( volatile u32& Target, u32 value );
extern u32 AtomicExchangeAdd( volatile u32& Target, u32 value );
extern u32 AtomicIncrement( volatile u32& Target );
extern u32 AtomicDecrement( volatile u32& Target );
extern s32 AtomicExchange( volatile s32& Target, s32 value );
extern s32 AtomicExchangeAdd( volatile s32& Target, u32 value );
extern s32 AtomicIncrement( volatile s32& Target );
extern s32 AtomicDecrement( volatile s32& Target );
extern void* _AtomicExchangePointer( void * volatile * const target, void* const value );
extern void* _AtomicCompareExchangePointer( void * volatile * const target, void* const value, void* const comparand );
#define AtomicExchangePointer( target, value ) \
_InterlockedExchangePointer( &target, value )
#define AtomicCompareExchangePointer( target, value, comparand ) \
_InterlockedCompareExchangePointer( &target, value, comparand )
}