ROOT::Internal::RTaskArenaWrapper Class Reference

Wrapper for tbb::task_arena.

Wrapper over tbb::task_arena.

Necessary in order to keep tbb away from ROOT headers. This class is thought out to be used as a singleton.

This class is a wrapper over tbb::task_arena, in order to keep TBB away from ROOT's headers. We keep a single global instance to be used by any parallel ROOT class with TBB as a backend.

TThreadExecutor, IMT and any class relying on TBB will get a pointer to the scheduler through ROOT::Internal::GetGlobalTaskArena(), which will return areference to the only pointer to the TBB scheduler that will be active in any ROOT Process.

Examples:

root[] auto gTA = ROOT::Internal::GetGlobalTaskArena(nWorkers) //get a shared_ptr to the global arena and initialize
                                                               //it with nWorkers. Enable thread safety in ROOT
root[] gTA->TaskArenaSize() // Get the current size of the arena (number of worker threads)
root[] gTA->Access() //std::unique_ptr to the internal tbb::task_arena for interacting directly with it (needed to
                     //call operations such as execute)
root[] gTA->Access().max_concurrency() // call to tbb::task_arena::max_concurrency()

Definition at line 64 of file RTaskArena.hxx.

Classes
struct	Attach
	Marker for attaching to an existing tbb::task_arena. More...

Public Member Functions
	RTaskArenaWrapper (Attach)
	Initializes the tbb::task_arena within RTaskArenaWrapper by attaching to an existing arena.
	RTaskArenaWrapper (unsigned maxConcurrency=0)
	Initializes the tbb::task_arena within RTaskArenaWrapper.
	~RTaskArenaWrapper ()
ROOT::ROpaqueTaskArena &	Access ()
	Provides access to the wrapped tbb::task_arena.

Static Public Member Functions
static unsigned	TaskArenaSize ()

Private Attributes
std::unique_ptr< ROOT::ROpaqueTaskArena >	fTBBArena

Static Private Attributes
static unsigned	fNWorkers = 0u

Friends
std::shared_ptr< ROOT::Internal::RTaskArenaWrapper >	GetGlobalTaskArena (unsigned, ROOT::EIMTConfig)

#include <ROOT/RTaskArena.hxx>

Constructor & Destructor Documentation

~RTaskArenaWrapper()

ROOT::Internal::RTaskArenaWrapper::~RTaskArenaWrapper

(

)

Definition at line 125 of file RTaskArena.cxx.

RTaskArenaWrapper() [1/2]

ROOT::Internal::RTaskArenaWrapper::RTaskArenaWrapper

(

unsigned

maxConcurrency = 0

)

Initializes the tbb::task_arena within RTaskArenaWrapper.

• Can't be reinitialized
• Checks for CPU bandwidth control and avoids oversubscribing
• If no BC in place and maxConcurrency<1, defaults to the default tbb number of threads, which is CPU affinity aware

Definition at line 93 of file RTaskArena.cxx.

RTaskArenaWrapper() [2/2]

ROOT::Internal::RTaskArenaWrapper::RTaskArenaWrapper

(

RTaskArenaWrapper::Attach

)

Initializes the tbb::task_arena within RTaskArenaWrapper by attaching to an existing arena.

• Can't be reinitialized

Definition at line 117 of file RTaskArena.cxx.

Member Function Documentation

Access()

ROOT::ROpaqueTaskArena & ROOT::Internal::RTaskArenaWrapper::Access

(

)

Provides access to the wrapped tbb::task_arena.

Definition at line 139 of file RTaskArena.cxx.

TaskArenaSize()

unsigned ROOT::Internal::RTaskArenaWrapper::TaskArenaSize ( )

static

Definition at line 132 of file RTaskArena.cxx.

Friends And Related Symbol Documentation

GetGlobalTaskArena

std::shared_ptr< ROOT::Internal::RTaskArenaWrapper > GetGlobalTaskArena ( unsigned maxConcurrency, ROOT::EIMTConfig config )

friend

Definition at line 145 of file RTaskArena.cxx.

Member Data Documentation

fNWorkers

unsigned ROOT::Internal::RTaskArenaWrapper::fNWorkers = 0u

staticprivate

Definition at line 77 of file RTaskArena.hxx.

fTBBArena

std::unique_ptr<ROOT::ROpaqueTaskArena> ROOT::Internal::RTaskArenaWrapper::fTBBArena

private

Definition at line 76 of file RTaskArena.hxx.

Libraries for ROOT::Internal::RTaskArenaWrapper:

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

• core/imt/inc/ROOT/RTaskArena.hxx
• core/imt/src/RTaskArena.cxx