#include <itkThreadPool.h>

Detailed Description

Thread pool maintains a constant number of threads.

Thread pool is called and initialized from within the PoolMultiThreader. Initially the thread pool is started with GlobalDefaultNumberOfThreads. The jobs are submitted via AddWork method.

This implementation heavily borrows from: https://github.com/progschj/ThreadPool

Definition at line 55 of file itkThreadPool.h.

Inheritance diagram for itk::ThreadPool:

Collaboration diagram for itk::ThreadPool:

Public Types
using	ConstPointer = SmartPointer< const Self >

using	Pointer = SmartPointer< Self >

using	Self = ThreadPool

using	Superclass = Object

Public Types inherited from itk::Object
using	ConstPointer = SmartPointer< const Self >

using	Pointer = SmartPointer< Self >

using	Self = Object

using	Superclass = LightObject

Public Types inherited from itk::LightObject
using	ConstPointer = SmartPointer< const Self >

using	Pointer = SmartPointer< Self >

using	Self = LightObject

Public Member Functions
void	AddThreads (ThreadIdType count)

ThreadIdType	GetMaximumNumberOfThreads () const

const char *	GetNameOfClass () const override

int	GetNumberOfCurrentlyIdleThreads () const


template<class Function , class... Arguments>
auto	AddWork (Function &&function, Arguments &&... arguments) -> std::future< std::invoke_result_t< Function, Arguments... >>

Public Member Functions inherited from itk::Object
unsigned long	AddObserver (const EventObject &event, Command *)

unsigned long	AddObserver (const EventObject &event, Command *) const

unsigned long	AddObserver (const EventObject &event, std::function< void(const EventObject &)> function) const

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

void	Register () const override

void	RemoveAllObservers ()

void	RemoveObserver (unsigned long tag)

void	SetDebug (bool debugFlag) const

void	SetReferenceCount (int) override

void	UnRegister () const noexcept override

void	SetMetaDataDictionary (const MetaDataDictionary &rhs)

void	SetMetaDataDictionary (MetaDataDictionary &&rrhs)

virtual void	SetObjectName (std::string _arg)

virtual const std::string &	GetObjectName () const

Public Member Functions inherited from itk::LightObject
Pointer	Clone () const

virtual void	Delete ()

virtual int	GetReferenceCount () const

void	Print (std::ostream &os, Indent indent=0) const

Static Public Member Functions
static Pointer	GetInstance ()

static Pointer	New ()


static bool	GetDoNotWaitForThreads ()

static void	SetDoNotWaitForThreads (bool doNotWaitForThreads)

Static Public Member Functions inherited from itk::Object
static bool	GetGlobalWarningDisplay ()

static void	GlobalWarningDisplayOff ()

static void	GlobalWarningDisplayOn ()

static Pointer	New ()

static void	SetGlobalWarningDisplay (bool val)

Static Public Member Functions inherited from itk::LightObject
static void	BreakOnError ()

static Pointer	New ()

Protected Member Functions
void	CleanUp ()

std::mutex &	GetMutex () const

	ThreadPool ()

	~ThreadPool () override

Protected Member Functions inherited from itk::Object
	Object ()

bool	PrintObservers (std::ostream &os, Indent indent) const

void	PrintSelf (std::ostream &os, Indent indent) const override

virtual void	SetTimeStamp (const TimeStamp &timeStamp)

	~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 void	PrepareForFork ()

static void	ResumeFromFork ()

Private Member Functions
	itkGetGlobalDeclarationMacro (ThreadPoolGlobals, PimplGlobals)

Static Private Member Functions
static void	ThreadExecute ()

Private Attributes
std::condition_variable	m_Condition

bool	m_Stopping { false }

std::vector< std::thread >	m_Threads

std::deque< std::function< void()> >	m_WorkQueue

Static Private Attributes
static ThreadPoolGlobals *	m_PimplGlobals

Additional Inherited Members
Protected Attributes inherited from itk::LightObject
std::atomic< int >	m_ReferenceCount {}

Member Typedef Documentation

◆ ConstPointer

using itk::ThreadPool::ConstPointer = SmartPointer<const Self>

Definition at line 64 of file itkThreadPool.h.

◆ Pointer

using itk::ThreadPool::Pointer = SmartPointer<Self>

Definition at line 63 of file itkThreadPool.h.

◆ Self

using itk::ThreadPool::Self = ThreadPool

Standard class type aliases.

Definition at line 61 of file itkThreadPool.h.

◆ Superclass

using itk::ThreadPool::Superclass = Object

Definition at line 62 of file itkThreadPool.h.

Constructor & Destructor Documentation

◆ ThreadPool()

itk::ThreadPool::ThreadPool ( )

protected

◆ ~ThreadPool()

itk::ThreadPool::~ThreadPool ( )

inlineoverrideprotected

Definition at line 141 of file itkThreadPool.h.

Member Function Documentation

◆ AddThreads()

void itk::ThreadPool::AddThreads ( ThreadIdType count )

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

◆ AddWork()

template<class Function , class... Arguments>

auto itk::ThreadPool::AddWork	(	Function &&	function,
		Arguments &&...	arguments
	)		-> std::future<std::invoke_result_t<Function, Arguments...>>

inline

Add this job to the thread pool queue.

This method returns an std::future, and calling get()
will block until the result is ready. Example usage:

auto result = pool->AddWork([](int param) { return param; }, 7);

std::cout << result.get() << std::endl;

Definition at line 87 of file itkThreadPool.h.

◆ CleanUp()

void itk::ThreadPool::CleanUp ( )

protected

Stop the pool and release threads. To be called by the destructor and atfork.

◆ GetDoNotWaitForThreads()

static bool itk::ThreadPool::GetDoNotWaitForThreads ( )

static

Set/Get wait for threads. This function should be used carefully, probably only during static initialization phase to disable waiting for threads when ITK is built as a static library and linked into a shared library (Windows only).

◆ GetInstance()

static Pointer itk::ThreadPool::GetInstance ( )

static

Returns the global singleton instance of the ThreadPool

◆ GetMaximumNumberOfThreads()

ThreadIdType itk::ThreadPool::GetMaximumNumberOfThreads ( ) const

inline

Definition at line 109 of file itkThreadPool.h.

◆ GetMutex()

std::mutex& itk::ThreadPool::GetMutex ( ) const

protected

We need access to the mutex in AddWork, and the variable is only visible in the .cxx file, so this method returns it.

◆ GetNameOfClass()

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

overridevirtual

See also: LightObject::GetNameOfClass()

Reimplemented from itk::Object.

◆ GetNumberOfCurrentlyIdleThreads()

int itk::ThreadPool::GetNumberOfCurrentlyIdleThreads ( ) const

The approximate number of idle threads.

◆ itkGetGlobalDeclarationMacro()

itk::ThreadPool::itkGetGlobalDeclarationMacro	(	ThreadPoolGlobals	,
		PimplGlobals
	)

private

Only used to synchronize the global variable across static libraries.

◆ New()

static Pointer itk::ThreadPool::New ( )

static

Returns the global instance

◆ PrepareForFork()

static void itk::ThreadPool::PrepareForFork ( )

staticprotected

◆ ResumeFromFork()

static void itk::ThreadPool::ResumeFromFork ( )

staticprotected

◆ SetDoNotWaitForThreads()

static void itk::ThreadPool::SetDoNotWaitForThreads ( bool doNotWaitForThreads )

static

Set/Get wait for threads. This function should be used carefully, probably only during static initialization phase to disable waiting for threads when ITK is built as a static library and linked into a shared library (Windows only).

◆ ThreadExecute()

static void itk::ThreadPool::ThreadExecute ( )

staticprivate

The continuously running thread function

Member Data Documentation

◆ m_Condition

std::condition_variable itk::ThreadPool::m_Condition

private

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

Definition at line 159 of file itkThreadPool.h.

◆ m_PimplGlobals

ThreadPoolGlobals* itk::ThreadPool::m_PimplGlobals

staticprivate

To lock on the internal variables

Definition at line 169 of file itkThreadPool.h.

◆ m_Stopping

bool itk::ThreadPool::m_Stopping { false }

private

Definition at line 166 of file itkThreadPool.h.

◆ m_Threads

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

private

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

Definition at line 163 of file itkThreadPool.h.

◆ m_WorkQueue

std::deque<std::function<void()> > itk::ThreadPool::m_WorkQueue

private

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

Definition at line 155 of file itkThreadPool.h.

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

itkThreadPool.h

Detailed Description

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Static Protected Member Functions

Private Member Functions

Static Private Member Functions

Private Attributes

Static Private Attributes

Additional Inherited Members

Member Typedef Documentation

◆ ConstPointer

◆ Pointer

◆ Self

◆ Superclass

Constructor & Destructor Documentation

◆ ThreadPool()

◆ ~ThreadPool()

Member Function Documentation

◆ AddThreads()

◆ AddWork()

◆ CleanUp()

◆ GetDoNotWaitForThreads()

◆ GetInstance()

◆ GetMaximumNumberOfThreads()

◆ GetMutex()

◆ GetNameOfClass()

◆ GetNumberOfCurrentlyIdleThreads()

◆ itkGetGlobalDeclarationMacro()

◆ New()

◆ PrepareForFork()

◆ ResumeFromFork()

◆ SetDoNotWaitForThreads()

◆ ThreadExecute()

Member Data Documentation

◆ m_Condition

◆ m_PimplGlobals

◆ m_Stopping

◆ m_Threads

◆ m_WorkQueue