FTaskThreadBase Class Reference

Inheritance diagram for FTaskThreadBase:

Public Member Functions
	FTaskThreadBase ()
void	Setup (ENamedThreads::Type InThreadId, uint32 InPerThreadIDTLSSlot, FWorkerThread *InOwnerWorker)
void	InitializeForCurrentThread ()
ENamedThreads::Type	GetThreadId () const
virtual void	ProcessTasksUntilQuit (int32 QueueIndex)=0
virtual uint64	ProcessTasksUntilIdle (int32 QueueIndex)
virtual void	EnqueueFromThisThread (int32 QueueIndex, FBaseGraphTask *Task)
virtual void	RequestQuit (int32 QueueIndex)=0
virtual bool	EnqueueFromOtherThread (int32 QueueIndex, FBaseGraphTask *Task)
virtual void	WakeUp (int32 QueueIndex=0)=0
virtual bool	IsProcessingTasks (int32 QueueIndex)=0
virtual void	Tick () override
virtual bool	Init () override
virtual uint32	Run () override
virtual void	Stop () override
virtual void	Exit () override
virtual FSingleThreadRunnable *	GetSingleThreadInterface () override
Public Member Functions inherited from FRunnable
virtual	~FRunnable ()

Protected Attributes
ENamedThreads::Type	ThreadId
uint32	PerThreadIDTLSSlot
FThreadSafeCounter	IsStalled
TArray< FBaseGraphTask * >	NewTasks
FWorkerThread *	OwnerWorker

Detailed Description

FTaskThreadBase Base class for a thread that executes tasks This class implements the FRunnable API, but external threads don't use that because those threads are created elsewhere.

Constructor & Destructor Documentation

FTaskThreadBase()

FTaskThreadBase::FTaskThreadBase ( )

inline

Constructor, initializes everything to unusable values. Meant to be called from a "main" thread.

Member Function Documentation

EnqueueFromOtherThread()

virtual bool FTaskThreadBase::EnqueueFromOtherThread ( int32  QueueIndex, FBaseGraphTask *  Task  )

inlinevirtual

Queue a task, assuming that this thread is not the same as the current thread.

Parameters

QueueIndex,Queue	to enqueue into
Task;	Task to queue.

Reimplemented in FNamedTaskThread.

EnqueueFromThisThread()

virtual void FTaskThreadBase::EnqueueFromThisThread ( int32  QueueIndex, FBaseGraphTask *  Task  )

inlinevirtual

Queue a task, assuming that this thread is the same as the current thread. For named threads, these go directly into the private queue.

Parameters

QueueIndex,Queue	to enqueue for
Task	Task to queue.

Reimplemented in FNamedTaskThread.

Exit()

virtual void FTaskThreadBase::Exit ( void  )

inlineoverridevirtual

Called in the context of the aggregating thread to perform any cleanup.

Reimplemented from FRunnable.

GetSingleThreadInterface()

virtual FSingleThreadRunnable * FTaskThreadBase::GetSingleThreadInterface ( )

inlineoverridevirtual

Return single threaded interface when multithreading is disabled.

Reimplemented from FRunnable.

GetThreadId()

ENamedThreads::Type FTaskThreadBase::GetThreadId ( ) const

inline

Return the index of this thread.

Init()

virtual bool FTaskThreadBase::Init ( void  )

inlineoverridevirtual

Allows per runnable object initialization. NOTE: This is called in the context of the thread object that aggregates this, not the thread that passes this runnable to a new thread.

Returns

True if initialization was successful, false otherwise

Reimplemented from FRunnable.

InitializeForCurrentThread()

void FTaskThreadBase::InitializeForCurrentThread ( )

inline

A one-time call to set the TLS entry for this thread.

IsProcessingTasks()

virtual bool FTaskThreadBase::IsProcessingTasks ( int32  QueueIndex )

pure virtual

Return true if this thread is processing tasks. This is only a "guess" if you ask for a thread other than yourself because that can change before the function returns.

Parameters

QueueIndex,Queue

to request quit from

Implemented in FNamedTaskThread, and FTaskThreadAnyThread.

ProcessTasksUntilIdle()

virtual uint64 FTaskThreadBase::ProcessTasksUntilIdle ( int32  QueueIndex )

inlinevirtual

Used for named threads to start processing tasks until the thread is idle and RequestQuit has been called.

Reimplemented in FNamedTaskThread, and FTaskThreadAnyThread.

ProcessTasksUntilQuit()

virtual void FTaskThreadBase::ProcessTasksUntilQuit ( int32  QueueIndex )

pure virtual

Used for named threads to start processing tasks until the thread is idle and RequestQuit has been called.

Implemented in FNamedTaskThread, and FTaskThreadAnyThread.

RequestQuit()

virtual void FTaskThreadBase::RequestQuit ( int32  QueueIndex )

pure virtual

Will cause the thread to return to the caller when it becomes idle. Used to return from ProcessTasksUntilQuit for named threads or to shut down unnamed threads. CAUTION: This will not work under arbitrary circumstances. For example you should not attempt to stop unnamed threads unless they are known to be idle. Return requests for named threads should be submitted from that named thread as FReturnGraphTask does.

Parameters

QueueIndex,Queue

to request quit from

Implemented in FNamedTaskThread, and FTaskThreadAnyThread.

Run()

virtual uint32 FTaskThreadBase::Run ( void  )

inlineoverridevirtual

This is where all per object thread work is done. This is only called if the initialization was successful.

Returns

The exit code of the runnable object

Implements FRunnable.

Setup()

void FTaskThreadBase::Setup ( ENamedThreads::Type  InThreadId, uint32  InPerThreadIDTLSSlot, FWorkerThread *  InOwnerWorker  )

inline

Sets up some basic information for a thread. Meant to be called from a "main" thread. Also creates the stall event.

Parameters

InThreadId;	Thread index for this thread.
InPerThreadIDTLSSlot;	TLS slot to store the pointer to me into (later)

Stop()

virtual void FTaskThreadBase::Stop ( void  )

inlineoverridevirtual

This is called if a thread is requested to terminate early

Reimplemented from FRunnable.

Tick()

virtual void FTaskThreadBase::Tick ( )

inlineoverridevirtual

Tick single-threaded.

Implements FSingleThreadRunnable.

WakeUp()

virtual void FTaskThreadBase::WakeUp ( int32  QueueIndex = 0 )

pure virtual

Implemented in FNamedTaskThread, and FTaskThreadAnyThread.

Member Data Documentation

IsStalled

FThreadSafeCounter FTaskThreadBase::IsStalled

protected

Used to signal stalling. Not safe for synchronization in most cases.

NewTasks

TArray<FBaseGraphTask*> FTaskThreadBase::NewTasks

protected

Array of tasks for this task thread.

OwnerWorker

FWorkerThread* FTaskThreadBase::OwnerWorker

protected

back pointer to the owning FWorkerThread

PerThreadIDTLSSlot

uint32 FTaskThreadBase::PerThreadIDTLSSlot

protected

TLS SLot that we store the FTaskThread* this pointer in.

ThreadId

ENamedThreads::Type FTaskThreadBase::ThreadId

protected

Id / Index of this thread.

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The documentation for this class was generated from the following file:

• Engine/Source/Runtime/Core/Private/Async/TaskGraph.cpp