template<class T>
class ROOT::TThreadedObject< T >

A wrapper to make object instances thread private, lazily.

Template Parameters

T	Class of the object to be made thread private (e.g. TH1F)

A wrapper which makes objects thread private. The methods of the underlying object can be invoked via the the arrow operator. The object is created in a specific thread lazily, i.e. upon invocation of one of its methods. The correct object pointer from within a particular thread can be accessed with the overloaded arrow operator or with the Get method. In case an elaborate thread management is in place, e.g. in presence of stream of operations or "processing slots", it is also possible to manually select the correct object pointer explicitly.

Definition at line 107 of file TThreadedObject.hxx.

Public Member Functions
	TThreadedObject (const TThreadedObject &)=delete

template<class ... ARGS>
	TThreadedObject (ARGS &&... args)
	Construct the TThreaded object and the "model" of the thread private objects. More...

std::shared_ptr< T >	Get ()
	Access the pointer corresponding to the current slot. More...

std::shared_ptr< T >	GetAtSlot (unsigned i)
	Access a particular processing slot. More...

std::shared_ptr< T >	GetAtSlotUnchecked (unsigned i) const
	Access a particular slot which corresponds to a single thread. More...

std::shared_ptr< T >	Merge (TThreadedObjectUtils::MergeFunctionType< T > mergeFunction=TThreadedObjectUtils::MergeTObjects< T >)
	Merge all the thread private objects. More...

T *	operator-> ()
	Access the wrapped object and allow to call its methods. More...

void	SetAtSlot (unsigned i, std::shared_ptr< T > v)
	Set the value of a particular slot. More...

std::unique_ptr< T >	SnapshotMerge (TThreadedObjectUtils::MergeFunctionType< T > mergeFunction=TThreadedObjectUtils::MergeTObjects< T >)
	Merge all the thread private objects. More...

Static Public Attributes
static unsigned	fgMaxSlots = 64
	The maximum number of processing slots (distinct threads) which the instances can manage. More...

Private Member Functions
unsigned	GetThisSlotNumber ()
	Get the slot number for this threadID. More...

Private Attributes
unsigned	fCurrMaxSlotIndex = 0
	The maximum slot index. More...

std::vector< TDirectory * >	fDirectories
	A TDirectory per thread is kept. More...

bool	fIsMerged = false
	Remember if the objects have been merged already. More...

std::unique_ptr< T >	fModel
	Use to store a "model" of the object. More...

std::vector< std::shared_ptr< T > >	fObjPointers
	A pointer per thread is kept. More...

std::map< std::thread::id, unsigned >	fThrIDSlotMap
	A mapping between the thread IDs and the slots. More...

ROOT::TSpinMutex	fThrIDSlotMutex
	Mutex to protect the ID-slot map access. More...

#include <ROOT/TThreadedObject.hxx>

Constructor & Destructor Documentation

◆ TThreadedObject() [1/2]

template<class T>

ROOT::TThreadedObject< T >::TThreadedObject ( const TThreadedObject< T > & )

delete

◆ TThreadedObject() [2/2]

template<class T>

template<class ... ARGS>

ROOT::TThreadedObject< T >::TThreadedObject ( ARGS &&... args )

inline

Construct the TThreaded object and the "model" of the thread private objects.

Template Parameters

ARGS	Arguments of the constructor of T

Definition at line 115 of file TThreadedObject.hxx.

Member Function Documentation

◆ Get()

template<class T>

std::shared_ptr<T> ROOT::TThreadedObject< T >::Get ( )

inline

Access the pointer corresponding to the current slot.

This method is not adequate for being called inside tight loops as it implies a lookup in a mapping between the threadIDs and the slot indices. A good practice consists in copying the pointer onto the stack and proceed with the loop as shown in this work item (psudo-code) which will be sent to different threads:

auto workItem = [](){
   auto objPtr = tthreadedObject.Get();
   for (auto i : ROOT::TSeqI(1000)) {
      // tthreadedObject->FastMethod(i); // don't do this! Inefficient!
      objPtr->FastMethod(i);
   }
}

Definition at line 176 of file TThreadedObject.hxx.

◆ GetAtSlot()

template<class T>

std::shared_ptr<T> ROOT::TThreadedObject< T >::GetAtSlot ( unsigned i )

inline

Access a particular processing slot.

This method is thread-unsafe: it cannot be invoked from two different threads with the same argument.

Definition at line 132 of file TThreadedObject.hxx.

◆ GetAtSlotUnchecked()

template<class T>

std::shared_ptr<T> ROOT::TThreadedObject< T >::GetAtSlotUnchecked ( unsigned i ) const

inline

Access a particular slot which corresponds to a single thread.

This is in general faster than the GetAtSlot method but it is responsibility of the caller to make sure that an object is initialised for the particular slot.

Definition at line 156 of file TThreadedObject.hxx.

◆ GetThisSlotNumber()

template<class T>

unsigned ROOT::TThreadedObject< T >::GetThisSlotNumber ( )

inlineprivate

Get the slot number for this threadID.

Definition at line 228 of file TThreadedObject.hxx.

◆ Merge()

template<class T>

std::shared_ptr<T> ROOT::TThreadedObject< T >::Merge ( TThreadedObjectUtils::MergeFunctionType< T > mergeFunction = TThreadedObjectUtils::MergeTObjects<T> )

inline

Merge all the thread private objects.

Can be called once: it does not create any new object but destroys the present bookkeping collapsing all objects into the one at slot 0.

Definition at line 190 of file TThreadedObject.hxx.

◆ operator->()

template<class T>

T* ROOT::TThreadedObject< T >::operator-> ( )

inline

Access the wrapped object and allow to call its methods.

Definition at line 182 of file TThreadedObject.hxx.

◆ SetAtSlot()

template<class T>

void ROOT::TThreadedObject< T >::SetAtSlot	(	unsigned	i,
		std::shared_ptr< T >	v
	)

inline

Set the value of a particular slot.

Definition at line 147 of file TThreadedObject.hxx.

◆ SnapshotMerge()

template<class T>

std::unique_ptr<T> ROOT::TThreadedObject< T >::SnapshotMerge ( TThreadedObjectUtils::MergeFunctionType< T > mergeFunction = TThreadedObjectUtils::MergeTObjects<T> )

inline

Merge all the thread private objects.

Can be called many times. It does create a new instance of class T to represent the "Sum" object. This method is not thread safe: correct or acceptable behaviours depend on the nature of T and of the merging function.

Definition at line 206 of file TThreadedObject.hxx.

Member Data Documentation

◆ fCurrMaxSlotIndex

template<class T>

unsigned ROOT::TThreadedObject< T >::fCurrMaxSlotIndex = 0

private

The maximum slot index.

Definition at line 223 of file TThreadedObject.hxx.

◆ fDirectories

template<class T>

std::vector<TDirectory*> ROOT::TThreadedObject< T >::fDirectories

private

A TDirectory per thread is kept.

Definition at line 221 of file TThreadedObject.hxx.

◆ fgMaxSlots

template<class T>

unsigned ROOT::TThreadedObject< T >::fgMaxSlots = 64

static

The maximum number of processing slots (distinct threads) which the instances can manage.

Definition at line 109 of file TThreadedObject.hxx.

◆ fIsMerged

template<class T>

bool ROOT::TThreadedObject< T >::fIsMerged = false

private

Remember if the objects have been merged already.

Definition at line 224 of file TThreadedObject.hxx.

◆ fModel

template<class T>

std::unique_ptr<T> ROOT::TThreadedObject< T >::fModel

private

Use to store a "model" of the object.

Definition at line 219 of file TThreadedObject.hxx.

◆ fObjPointers

template<class T>

std::vector<std::shared_ptr<T> > ROOT::TThreadedObject< T >::fObjPointers

private

A pointer per thread is kept.

Definition at line 220 of file TThreadedObject.hxx.

◆ fThrIDSlotMap

template<class T>

std::map<std::thread::id, unsigned> ROOT::TThreadedObject< T >::fThrIDSlotMap

private

A mapping between the thread IDs and the slots.

Definition at line 222 of file TThreadedObject.hxx.

◆ fThrIDSlotMutex

template<class T>

ROOT::TSpinMutex ROOT::TThreadedObject< T >::fThrIDSlotMutex

private

Mutex to protect the ID-slot map access.

Definition at line 225 of file TThreadedObject.hxx.

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

core/thread/inc/ROOT/TThreadedObject.hxx

template<class T> class ROOT::TThreadedObject< T >

Public Member Functions

Static Public Attributes

Private Member Functions

Private Attributes

Constructor & Destructor Documentation

◆ TThreadedObject() [1/2]

◆ TThreadedObject() [2/2]

Member Function Documentation

◆ Get()

◆ GetAtSlot()

◆ GetAtSlotUnchecked()

◆ GetThisSlotNumber()

◆ Merge()

◆ operator->()

◆ SetAtSlot()

◆ SnapshotMerge()

Member Data Documentation

◆ fCurrMaxSlotIndex

◆ fDirectories

◆ fgMaxSlots

◆ fIsMerged

◆ fModel

◆ fObjPointers

◆ fThrIDSlotMap

◆ fThrIDSlotMutex

template<class T>
class ROOT::TThreadedObject< T >