thread-pool.h File Reference

Typedefs
typedef void *(*	TPGetTaskFunc) (void *qargs)
typedef void(*	TPWorkFunc) (void *work, int cookie)
typedef void(*	TPFinalFunc) (void *qargs, void *work)

Functions
signed int	get_status_label (void)
int	run_threads (int n_threads, TPWorkFunc work, TPGetTaskFunc get_task, TPFinalFunc final, void *queue_args, int max, int cpu_num, int cpu_groupsize, int cpu_offset)

Detailed Description

Thread pool.

Typedef Documentation

TPFinalFunc

typedef void(* TPFinalFunc) (void *qargs, void *work)

Parameters

qargs	The queue_args pointer which was given to run_threads.
work	The pointer which was returned by your get_task function.

This function is called, non-reentrantly, after each work item has been completed. A typical use might be to update some counters inside qargs according to fields withing work which were filled by your 'work' function.

TPGetTaskFunc

typedef void *(* TPGetTaskFunc) (void *qargs)

qargs: The queue_args pointer which was given to run_threads().

Returns

a pointer which will be passed to the worker function.

This function is called, non-reentrantly, to get a new work item to give to your work function. The stuff you need to generate the new work item should have been stored in qargs which was passed to run_threads.

TPWorkFunc

typedef void(* TPWorkFunc) (void *work, int cookie)

Parameters

work	The queue_args pointer which was given to run_threads.
cookie	A small integral number which is guaranteed to be unique among all currently running threads.

This function is called, reentrantly, for each work item.

Function Documentation

run_threads()

int run_threads	(	int	n_threads,
		TPWorkFunc	work,
		TPGetTaskFunc	get_task,
		TPFinalFunc	final,
		void *	queue_args,
		int	max,
		int	cpu_num,
		int	cpu_groupsize,
		int	cpu_offset
	)

Parameters

n_threads	The number of threads to run in parallel
work	The function to be called to do the work
get_task	The function which will determine the next unassigned task
final	The function which will be called to clean up after a task
queue_args	A pointer to any data required to determine the next task
max	Stop calling get_task after starting this number of jobs
cpu_num	Ignored
cpu_groupsize	Ignored
cpu_offset	Ignored

get_task will be called every time a worker is idle. It returns either NULL, indicating that no further work is available, or a pointer which will be passed to work.

final will be called once per image, and will be given both queue_args and the last task pointer.

get_task and final will be called only under lock, and so do NOT need to be re-entrant or otherwise thread safe. 'work', of course, needs to be thread safe.

Work will stop after max tasks have been processed whether get_task returned NULL or not. If max is zero, all tasks will be processed.

Returns

The number of tasks completed.