itk::ThreadPool Class Reference

#include <itkThreadPool.h>

Inheritance diagram for itk::ThreadPool:

Collaboration diagram for itk::ThreadPool:

Detailed Description

Thread pool maintains a constant number of threads.

Thread pool is called and initialized from within the MultiThreader. Initially the thread pool is started with GlobalDefaultNumberOfThreads. The ThreadJob class is used to submit jobs to the thread pool. The ThreadJob's necessary members need to be set and then the ThreadJob can be passed to the ThreadPool by calling its AddWork method. One can then wait for the job by calling the WaitForJob method.

When thread pool is in use by the MultiThreader, invoking SetNumberOfThreads on MultiThreader will only increase the number of jobs submitted to the ThreadPool, it will not increase the number of threads. This trick can be used to increase the number of chunks, which can help load balancing in case the algorithm takes more time for some parts of the image, and there is relatively small overhead for chunking (splitting the image for processing).

If more threads are required, e.g. in case when Barrier is used, AddThreads method should be invoked.

Definition at line 61 of file itkThreadPool.h.

Public Types
typedef SmartPointer< const Self >	ConstPointer
typedef SmartPointer< Self >	Pointer
typedef ThreadPool	Self
typedef ThreadJob::Semaphore	Semaphore
typedef Object	Superclass
Public Types inherited from itk::Object
typedef SmartPointer< const Self >	ConstPointer
typedef SmartPointer< Self >	Pointer
typedef Object	Self
typedef LightObject	Superclass
Public Types inherited from itk::LightObject
typedef SmartPointer< const Self >	ConstPointer
typedef SmartPointer< Self >	Pointer
typedef LightObject	Self

Public Member Functions
void	AddThreads (ThreadIdType count)
void	AddWork (const ThreadJob &job)
virtual const char *	GetNameOfClass () const
int	GetNumberOfCurrentlyIdleThreads () const
void	WaitForJob (Semaphore &jobSemaphore)
Public Member Functions inherited from itk::Object
unsigned long	AddObserver (const EventObject &event, Command *)
unsigned long	AddObserver (const EventObject &event, Command *) const
virtual LightObject::Pointer	CreateAnother () const override
virtual void	DebugOff () const
virtual void	DebugOn () const
Command *	GetCommand (unsigned long tag)
bool	GetDebug () const
MetaDataDictionary &	GetMetaDataDictionary ()
const MetaDataDictionary &	GetMetaDataDictionary () const
virtual ModifiedTimeType	GetMTime () const
virtual const TimeStamp &	GetTimeStamp () const
bool	HasObserver (const EventObject &event) const
void	InvokeEvent (const EventObject &)
void	InvokeEvent (const EventObject &) const
virtual void	Modified () const
virtual void	Register () const override
void	RemoveAllObservers ()
void	RemoveObserver (unsigned long tag)
void	SetDebug (bool debugFlag) const
void	SetMetaDataDictionary (const MetaDataDictionary &rhs)
virtual void	SetReferenceCount (int) override
virtual void	UnRegister () const noexceptoverride
virtual void	SetObjectName (std::string _arg)
virtual const std::string &	GetObjectName () const
Public Member Functions inherited from itk::LightObject
virtual void	Delete ()
virtual int	GetReferenceCount () const
	itkCloneMacro (Self)
void	Print (std::ostream &os, Indent indent=0) const

Static Public Member Functions
static ThreadIdType	GetGlobalDefaultNumberOfThreads ()
static ThreadIdType	GetGlobalDefaultNumberOfThreadsByPlatform ()
static Pointer	GetInstance ()
static Pointer	New ()
Static Public Member Functions inherited from itk::Object
static bool	GetGlobalWarningDisplay ()
static void	GlobalWarningDisplayOff ()
static void	GlobalWarningDisplayOn ()
static Pointer	New ()
static void	SetGlobalWarningDisplay (bool flag)
Static Public Member Functions inherited from itk::LightObject
static void	BreakOnError ()
static Pointer	New ()

Protected Member Functions
void	AddThread ()
void	DeleteThreads ()
	ThreadPool ()
virtual	~ThreadPool () override
Protected Member Functions inherited from itk::Object
	Object ()
bool	PrintObservers (std::ostream &os, Indent indent) const
virtual void	PrintSelf (std::ostream &os, Indent indent) const override
virtual void	SetTimeStamp (const TimeStamp &time)
virtual	~Object () override
Protected Member Functions inherited from itk::LightObject
virtual LightObject::Pointer	InternalClone () const
	LightObject ()
virtual void	PrintHeader (std::ostream &os, Indent indent) const
virtual void	PrintTrailer (std::ostream &os, Indent indent) const
virtual	~LightObject ()

Static Protected Member Functions
static bool	PlatformClose (ThreadProcessIdType &threadId)
static void	PlatformCreate (Semaphore &semaphore)
static void	PlatformDelete (Semaphore &semaphore)
static void	PlatformSignal (Semaphore &semaphore)
static void	PlatformWait (Semaphore &semaphore)

Static Private Member Functions
static ITK_THREAD_RETURN_TYPE	ThreadExecute (void *param)

Private Attributes
bool	m_ExceptionOccurred
std::vector< ThreadProcessIdType >	m_Threads
Semaphore	m_ThreadsSemaphore
std::deque< ThreadJob >	m_WorkQueue

Static Private Attributes
static SimpleFastMutexLock	m_Mutex
static Pointer	m_ThreadPoolInstance

Additional Inherited Members
Protected Attributes inherited from itk::LightObject
AtomicInt< int >	m_ReferenceCount

Member Typedef Documentation

typedef SmartPointer<const Self> itk::ThreadPool::ConstPointer

Definition at line 69 of file itkThreadPool.h.

typedef SmartPointer< Self > itk::ThreadPool::Pointer

Definition at line 68 of file itkThreadPool.h.

typedef ThreadPool itk::ThreadPool::Self

Standard class typedefs.

Definition at line 66 of file itkThreadPool.h.

typedef ThreadJob::Semaphore itk::ThreadPool::Semaphore

Definition at line 71 of file itkThreadPool.h.

typedef Object itk::ThreadPool::Superclass

Definition at line 67 of file itkThreadPool.h.

Constructor & Destructor Documentation

itk::ThreadPool::ThreadPool ( )

protected

virtual itk::ThreadPool::~ThreadPool ( )

overrideprotectedvirtual

Member Function Documentation

void itk::ThreadPool::AddThread ( )

protected

Called to add a thread to the thread pool. This method add a thread to the thread pool and pushes the thread handle into the m_Threads vector.

void itk::ThreadPool::AddThreads

(

ThreadIdType

count

)

Can call this method if we want to add extra threads to the pool.

void itk::ThreadPool::AddWork

(

const ThreadJob &

job

)

Add this job to the thread pool queue. All data members of the ThreadJob must be filled. The semaphore pointer must point to a valid semaphore structure. AddWork will initialize that semaphore, and the invoker must pass it to WaitForJob in order to wait for the job's completion.

void itk::ThreadPool::DeleteThreads ( )

protected

Platform-specific function to clean up all the threads.

static ThreadIdType itk::ThreadPool::GetGlobalDefaultNumberOfThreads ( )

static

Examines environment variables and falls back to hyper-threaded core count

static ThreadIdType itk::ThreadPool::GetGlobalDefaultNumberOfThreadsByPlatform ( )

static

Platform specific number of threads

static Pointer itk::ThreadPool::GetInstance ( )

static

Returns the global singleton instance of the ThreadPool

virtual const char* itk::ThreadPool::GetNameOfClass ( ) const

virtual

Run-time type information (and related methods).

Reimplemented from itk::Object.

int itk::ThreadPool::GetNumberOfCurrentlyIdleThreads

(

)

const

The approximate number of idle threads.

static Pointer itk::ThreadPool::New ( )

static

Returns the global instance

static bool itk::ThreadPool::PlatformClose ( ThreadProcessIdType &  threadId )

staticprotected

static void itk::ThreadPool::PlatformCreate ( Semaphore &  semaphore )

staticprotected

static void itk::ThreadPool::PlatformDelete ( Semaphore &  semaphore )

staticprotected

static void itk::ThreadPool::PlatformSignal ( Semaphore &  semaphore )

staticprotected

static void itk::ThreadPool::PlatformWait ( Semaphore &  semaphore )

staticprotected

static ITK_THREAD_RETURN_TYPE itk::ThreadPool::ThreadExecute ( void *  param )

staticprivate

The continuously running thread function

void itk::ThreadPool::WaitForJob

(

Semaphore &

jobSemaphore

)

This method blocks until the given job has finished executing.

Member Data Documentation

bool itk::ThreadPool::m_ExceptionOccurred

private

Set if exception occurs

Definition at line 126 of file itkThreadPool.h.

SimpleFastMutexLock itk::ThreadPool::m_Mutex

staticprivate

To lock on the internal variables

Definition at line 148 of file itkThreadPool.h.

Pointer itk::ThreadPool::m_ThreadPoolInstance

staticprivate

Definition at line 150 of file itkThreadPool.h.

std::vector<ThreadProcessIdType> itk::ThreadPool::m_Threads

private

Vector to hold all thread handles. Thread handles are used to delete the threads.

Definition at line 145 of file itkThreadPool.h.

Semaphore itk::ThreadPool::m_ThreadsSemaphore

private

When a thread is idle, it is waiting on m_ThreadsSemaphore. AddWork signals this semaphore to resume a (random) thread.

Definition at line 140 of file itkThreadPool.h.

std::deque<ThreadJob> itk::ThreadPool::m_WorkQueue

private

This is a list of jobs(ThreadJob) submitted to the thread pool. This is the only place where the jobs are submitted. Filled by AddWork, emptied by ThreadExecute.

Definition at line 135 of file itkThreadPool.h.

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

• itkThreadPool.h