farm.hpp File Reference

Farm pattern. More...

#include <iostream>
#include <vector>
#include <algorithm>
#include <ff/platforms/platform.h>
#include <ff/lb.hpp>
#include <ff/gt.hpp>
#include <ff/node.hpp>
#include <functional>

Include dependency graph for farm.hpp:

This graph shows which files directly or indirectly include this file:

Classes
class	ff::ff_farm< lb_t, gt_t >
	The Farm skeleton, with Emitter (lb_t) and Collector (gt_t). More...
class	ff::ofarm_lb
	Ordered farm emitter. More...
class	ff::ofarm_gt
	Ordered farm Collector. More...
class	ff::ff_ofarm
	The ordered Farm skeleton. More...
class	ff::ff_minode
	Multiple input ff_node (the MPSC mediator) More...
class	ff::ff_monode
	Multiple output ff_node (the SPMC mediator) More...

Namespaces
	ff
	The principal namespace for the FastFlow library.

Detailed Description

Farm pattern.

It works on a stream of tasks. Workers are non-blocking threads not tasks. It is composed by: Emitter (E), Workers (W), Collector (C). They all are C++ objects. Overall, it has one (optional) input stream and one (optional) output stream. Emitter gets stream items (tasks, i.e. C++ objects) and disptach them to Workers (activating svc method). On svn return (or ff_send_out call), tasks are sent to Collector that gather them and output them in the output stream.

Dispatching policy can be configured in the Emitter. Gathering policy in the Collector.

In case of no output stream the Collector is usually not needed. Emitter should always exist, even with no input stream.

There exists several variants of the farm pattern, including

• Master-worker: no collector, tasks from Workers return to Emitter
• Ordering farm: default emitter and collector, tasks are gathered in the same order they are dispatched

Todo:

Includes classes at different levels. To be split sooner or later. High level farm function to be wrapped in a separate class.