Gaudi::SerialTaskQueue Class Reference

Class for a generic serial queue of tasks (modeled on the Intel Threading Building Blocks Design Pattern "Local Serializer"). More...

#include <GaudiKernel/SerialTaskQueue.h>

Collaboration diagram for Gaudi::SerialTaskQueue:

Classes
class	SerialWorkItem
	Wrapper for the WorkItem class for internal concurrency bookkeeping. More...
class	SerialWorkItemRunner
	Helper class to wrap a SerialWorkItem in a tbb::task. More...
class	WorkItem
	Base class for the task to be executed by the serial queue. More...

Public Member Functions
	SerialTaskQueue ()
	Default constructor. More...
virtual	~SerialTaskQueue ()
	Block until all the enqueued tasks are completed. More...
void	add (WorkItem *item)
	Enqueue a WorkItem for execution. More...
void	noteCompletion ()
	Method used by the tasks to trigger the execution of the next task in the queue. More...
void	wait () const
	Block until all the currently enqueued tasks are completed. More...

Private Member Functions
void	i_startNextItem ()

Private Attributes
std::atomic< int >	m_count
	Counter of the currently running tasks. More...
tbb::concurrent_queue< SerialWorkItem * >	m_queue
	Queue of the tasks to be executed. More...

Detailed Description

Class for a generic serial queue of tasks (modeled on the Intel Threading Building Blocks Design Pattern "Local Serializer").

Users of SerialTaskQueue must define the tasks to be executed specializing the class SerialTaskQueue::WorkItem, implementing the method WorkItem::run().

Tasks are enqueued via the method SerialTaskQueue::add(WorkItem*).

When the instance goes out of scope (or is destructed), the thread blocks until all the enqueued tasks are completed.

Author

Marco Clemencic

Definition at line 33 of file SerialTaskQueue.h.

Constructor & Destructor Documentation

Gaudi::SerialTaskQueue::SerialTaskQueue

(

)

Default constructor.

Definition at line 13 of file SerialTaskQueue.cpp.

: m_count( 0 ) {}

Gaudi::SerialTaskQueue::~SerialTaskQueue ( )

virtual

Block until all the enqueued tasks are completed.

Definition at line 15 of file SerialTaskQueue.cpp.

{ wait(); }

Member Function Documentation

void Gaudi::SerialTaskQueue::add

(

WorkItem *

item

)

Enqueue a WorkItem for execution.

Definition at line 19 of file SerialTaskQueue.cpp.

  {
    m_queue.push( new SerialWorkItem( item, this ) );
    if ( ++m_count == 1 ) i_startNextItem();
  }

void Gaudi::SerialTaskQueue::i_startNextItem ( )

private

Definition at line 37 of file SerialTaskQueue.cpp.

  {
    SerialWorkItem* item = 0;
    m_queue.try_pop( item );
    tbb::task::enqueue( *new ( tbb::task::allocate_root() ) SerialWorkItemRunner( item ) );
  }

void Gaudi::SerialTaskQueue::noteCompletion

(

)

Method used by the tasks to trigger the execution of the next task in the queue.

Definition at line 25 of file SerialTaskQueue.cpp.

  {
    if ( --m_count != 0 ) i_startNextItem();
  }

void Gaudi::SerialTaskQueue::wait

(

)

const

Block until all the currently enqueued tasks are completed.

Note

while a thread is waiting for the tasks to be completes, another may still enqueue other tasks.

Definition at line 30 of file SerialTaskQueue.cpp.

  {
    // wait until the queue is empty and all the tasks are completed
    while ( ( !m_queue.empty() ) || m_count ) {
    }
  }

Member Data Documentation

std::atomic<int> Gaudi::SerialTaskQueue::m_count

private

Counter of the currently running tasks.

Definition at line 105 of file SerialTaskQueue.h.

tbb::concurrent_queue<SerialWorkItem*> Gaudi::SerialTaskQueue::m_queue

private

Queue of the tasks to be executed.

Definition at line 107 of file SerialTaskQueue.h.

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

• GaudiKernel/GaudiKernel/SerialTaskQueue.h
• GaudiKernel/src/Lib/SerialTaskQueue.cpp