Class defining a thread pool for executing algorithms in multi-threaded mode. Thread pool allocates requested amount of threads and keep them alive (in sleep mode when unused) during thread pool lifetime. The same pool can be used by multiple consumers, including nested multi-threading algorithms and concurrent threads: More...

#include <OSD_ThreadPool.hxx>

Inheritance diagram for OSD_ThreadPool:

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Data Structures
class	EnumeratedThread
	Thread with back reference to thread pool and thread index in it. More...

class	Job
	Auxiliary wrapper class for thread function. More...

class	JobInterface
	Thread function interface. More...

class	JobRange
	Auxiliary class which ensures exclusive access to iterators of processed data pool. More...

class	Launcher
	Launcher object locking a subset of threads (or all threads) in a thread pool to perform parallel execution of the job. More...

Public Member Functions
	OSD_ThreadPool (int theNbThreads=-1)
	Main constructor. Application may consider specifying more threads than actually available (OSD_Parallel::NbLogicalProcessors()) and set up NbDefaultThreadsToLaunch() to a smaller value so that concurrent threads will be able using single Thread Pool instance more efficiently.

virtual	~OSD_ThreadPool ()
	Destructor.

bool	HasThreads () const
	Return TRUE if at least 2 threads are available (including self-thread).

int	LowerThreadIndex () const
	Return the lower thread index.

int	UpperThreadIndex () const
	Return the upper thread index (last index is reserved for self-thread).

int	NbThreads () const
	Return the number of threads; >= 1.

int	NbDefaultThreadsToLaunch () const
	Return maximum number of threads to be locked by a single Launcher object by default; the entire thread pool size is returned by default.

void	SetNbDefaultThreadsToLaunch (int theNbThreads)
	Set maximum number of threads to be locked by a single Launcher object by default. Should be set BEFORE first usage.

bool	IsInUse ()
	Checks if thread pools has active consumers.

void	Init (int theNbThreads)
	Reinitialize the thread pool with a different number of threads. Should be called only with no active jobs, or exception Standard_ProgramError will be thrown!

Public Member Functions inherited from Standard_Transient
	Standard_Transient ()
	Empty constructor.

	Standard_Transient (const Standard_Transient &)
	Copy constructor – does nothing.

Standard_Transient &	operator= (const Standard_Transient &)
	Assignment operator, needed to avoid copying reference counter.

virtual	~Standard_Transient ()
	Destructor must be virtual.

virtual const opencascade::handle< Standard_Type > &	DynamicType () const
	Returns a type descriptor about this object.

Standard_Boolean	IsInstance (const opencascade::handle< Standard_Type > &theType) const
	Returns a true value if this is an instance of Type.

Standard_Boolean	IsInstance (const Standard_CString theTypeName) const
	Returns a true value if this is an instance of TypeName.

Standard_Boolean	IsKind (const opencascade::handle< Standard_Type > &theType) const
	Returns true if this is an instance of Type or an instance of any class that inherits from Type. Note that multiple inheritance is not supported by OCCT RTTI mechanism.

Standard_Boolean	IsKind (const Standard_CString theTypeName) const
	Returns true if this is an instance of TypeName or an instance of any class that inherits from TypeName. Note that multiple inheritance is not supported by OCCT RTTI mechanism.

Standard_Transient *	This () const
	Returns non-const pointer to this object (like const_cast). For protection against creating handle to objects allocated in stack or call from constructor, it will raise exception Standard_ProgramError if reference counter is zero.

Standard_Integer	GetRefCount () const noexcept
	Get the reference counter of this object.

void	IncrementRefCounter () noexcept
	Increments the reference counter of this object.

Standard_Integer	DecrementRefCounter () noexcept
	Decrements the reference counter of this object; returns the decremented value.

virtual void	Delete () const
	Memory deallocator for transient classes.

Static Public Member Functions
static const Handle< OSD_ThreadPool > &	DefaultPool (int theNbThreads=-1)
	Return (or create) a default thread pool. Number of threads argument will be considered only when called first time.

Static Public Member Functions inherited from Standard_Transient
static constexpr const char *	get_type_name ()
	Returns a type descriptor about this object.

static const opencascade::handle< Standard_Type > &	get_type_descriptor ()
	Returns type descriptor of Standard_Transient class.

Protected Member Functions
void	release ()
	Release threads.

Static Protected Member Functions
static void	performJob (Handle< Standard_Failure > &theFailure, OSD_ThreadPool::JobInterface *theJob, int theThreadIndex)
	Perform the job and catch exceptions.

Additional Inherited Members
Public Types inherited from Standard_Transient
typedef void	base_type
	Returns a type descriptor about this object.

Detailed Description

Class defining a thread pool for executing algorithms in multi-threaded mode. Thread pool allocates requested amount of threads and keep them alive (in sleep mode when unused) during thread pool lifetime. The same pool can be used by multiple consumers, including nested multi-threading algorithms and concurrent threads:

Thread pool can be used either by multi-threaded algorithm by creating OSD_ThreadPool::Launcher. The functor performing a job takes two parameters - Thread Index and Data Index: void operator(int theThreadIndex, int theDataIndex){} Multi-threaded algorithm may rely on Thread Index for allocating thread-local variables in array form, since the Thread Index is guaranteed to be within range OSD_ThreadPool::Lower() and OSD_ThreadPool::Upper().
Default thread pool (OSD_ThreadPool::DefaultPool()) can be used in general case, but application may prefer creating a dedicated pool for better control.
Default thread pool allocates the amount of threads considering concurrency level of the system (amount of logical processors). This can be overridden during OSD_ThreadPool construction or by calling OSD_ThreadPool::Init() (the pool should not be used!).
OSD_ThreadPool::Launcher reserves specific amount of threads from the pool for executing multi-threaded Job. Normally, single Launcher instance will occupy all threads available in thread pool, so that nested multi-threaded algorithms (within the same thread) and concurrent threads trying to use the same thread pool will run sequentially. This behavior is affected by OSD_ThreadPool::NbDefaultThreadsToLaunch() parameter and Launcher constructor, so that single Launcher instance will occupy not all threads in the pool allowing other threads to be used concurrently.
OSD_ThreadPool::Launcher locks thread one-by-one from thread pool in a thread-safe way.
Each working thread catches exceptions occurred during job execution, and Launcher will throw Standard_Failure in a caller thread on completed execution.

Constructor & Destructor Documentation

◆ OSD_ThreadPool()

OSD_ThreadPool::OSD_ThreadPool ( int theNbThreads = -1 )

Main constructor. Application may consider specifying more threads than actually available (OSD_Parallel::NbLogicalProcessors()) and set up NbDefaultThreadsToLaunch() to a smaller value so that concurrent threads will be able using single Thread Pool instance more efficiently.

Parameters

theNbThreads threads number to be created by pool (if -1 is specified then OSD_Parallel::NbLogicalProcessors() will be used)

◆ ~OSD_ThreadPool()

virtual OSD_ThreadPool::~OSD_ThreadPool ( )

virtual

Destructor.

Member Function Documentation

◆ DefaultPool()

static const Handle< OSD_ThreadPool > & OSD_ThreadPool::DefaultPool ( int theNbThreads = -1 )

static

Return (or create) a default thread pool. Number of threads argument will be considered only when called first time.

◆ HasThreads()

bool OSD_ThreadPool::HasThreads ( ) const

inline

Return TRUE if at least 2 threads are available (including self-thread).

◆ Init()

void OSD_ThreadPool::Init ( int theNbThreads )

Reinitialize the thread pool with a different number of threads. Should be called only with no active jobs, or exception Standard_ProgramError will be thrown!

◆ IsInUse()

bool OSD_ThreadPool::IsInUse ( )

Checks if thread pools has active consumers.

◆ LowerThreadIndex()

int OSD_ThreadPool::LowerThreadIndex ( ) const

inline

Return the lower thread index.

◆ NbDefaultThreadsToLaunch()

int OSD_ThreadPool::NbDefaultThreadsToLaunch ( ) const

inline

Return maximum number of threads to be locked by a single Launcher object by default; the entire thread pool size is returned by default.

◆ NbThreads()

int OSD_ThreadPool::NbThreads ( ) const

inline

Return the number of threads; >= 1.

◆ performJob()

static void OSD_ThreadPool::performJob	(	Handle< Standard_Failure > &	theFailure,
		OSD_ThreadPool::JobInterface *	theJob,
		int	theThreadIndex
	)

staticprotected

Perform the job and catch exceptions.

◆ release()

void OSD_ThreadPool::release ( )

protected

Release threads.

◆ SetNbDefaultThreadsToLaunch()

void OSD_ThreadPool::SetNbDefaultThreadsToLaunch ( int theNbThreads )

inline

Set maximum number of threads to be locked by a single Launcher object by default. Should be set BEFORE first usage.

◆ UpperThreadIndex()

int OSD_ThreadPool::UpperThreadIndex ( ) const

inline

Return the upper thread index (last index is reserved for self-thread).

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

OSD_ThreadPool.hxx

Data Structures

Public Member Functions

Static Public Member Functions

Protected Member Functions

Static Protected Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ OSD_ThreadPool()

◆ ~OSD_ThreadPool()

Member Function Documentation

◆ DefaultPool()

◆ HasThreads()

◆ Init()

◆ IsInUse()

◆ LowerThreadIndex()

◆ NbDefaultThreadsToLaunch()

◆ NbThreads()

◆ performJob()

◆ release()

◆ SetNbDefaultThreadsToLaunch()

◆ UpperThreadIndex()