scheduler_GEDF_NP.c File Reference

Global Earliest Deadline First (GEDF) non-preemptive scheduler for the threaded runtime of the C target of Lingua Franca. More...

#include "lf_types.h"
#include <assert.h>
#include "low_level_platform.h"
#include "environment.h"
#include "pqueue.h"
#include "reactor_threaded.h"
#include "scheduler_instance.h"
#include "scheduler_sync_tag_advance.h"
#include "scheduler.h"
#include "tracepoint.h"
#include "util.h"

Data Structures
struct	custom_scheduler_data_t

Macros
#define	NUMBER_OF_WORKERS   1

Typedefs
typedef struct custom_scheduler_data_t	custom_scheduler_data_t

Functions
void	lf_sched_init (environment_t *env, size_t number_of_workers, sched_params_t *params)
	Initialize the scheduler.
void	lf_sched_free (lf_scheduler_t *scheduler)
	Free the memory used by the scheduler.
reaction_t *	lf_sched_get_ready_reaction (lf_scheduler_t *scheduler, int worker_number)
	Ask the scheduler for one more reaction.
void	lf_sched_done_with_reaction (size_t worker_number, reaction_t *done_reaction)
	Inform the scheduler that worker thread 'worker_number' is done executing the 'done_reaction'.
void	lf_scheduler_trigger_reaction (lf_scheduler_t *scheduler, reaction_t *reaction, int worker_number)
	Inform the scheduler that worker thread 'worker_number' would like to trigger 'reaction' at the current tag.

Detailed Description

Global Earliest Deadline First (GEDF) non-preemptive scheduler for the threaded runtime of the C target of Lingua Franca.

Author

Soroush Bateni

Edward A. Lee

Marten Lohstroh

Copyright

(c) 2020-2024, The University of California at Berkeley. License: BSD 2-clause

At each tag, this scheduler prioritizes reactions with the smallest (inferred) deadline. An inferred deadline for reaction R is either an explicitly declared deadline or the declared deadline of a reaction that depends on R. This scheduler is non-preemptive, meaning that once a worker thread starts executing a reaction, it will execute that reaction to completion. The underlying thread scheduler, of course, could preempt the execution in favor of some other worker thread. This scheduler does not take into account execution times of reactions. Moreover, it does not prioritize reactions across distinct tags.

Macro Definition Documentation

NUMBER_OF_WORKERS

#define NUMBER_OF_WORKERS   1

Typedef Documentation

custom_scheduler_data_t

typedef struct custom_scheduler_data_t custom_scheduler_data_t

Function Documentation

lf_sched_done_with_reaction()

void lf_sched_done_with_reaction	(	size_t	worker_number,
		reaction_t *	done_reaction )

Inform the scheduler that worker thread 'worker_number' is done executing the 'done_reaction'.

Parameters

scheduler	The scheduler
worker_number	The worker number for the worker thread that has finished executing 'done_reaction'.
done_reaction	The reaction that is done.

lf_sched_free()

void lf_sched_free

(

lf_scheduler_t *

scheduler

)

Free the memory used by the scheduler.

This must be called when the scheduler is no longer needed.

lf_sched_get_ready_reaction()

reaction_t * lf_sched_get_ready_reaction	(	lf_scheduler_t *	scheduler,
		int	worker_number )

Ask the scheduler for one more reaction.

This function blocks until it can return a ready reaction for worker thread 'worker_number' or it is time for the worker thread to stop and exit (where a NULL value would be returned). This function assumes that the environment mutex is not locked.

Parameters

scheduler	The scheduler
worker_number	For the calling worker thread.

Returns

reaction_t* A reaction for the worker to execute. NULL if the calling worker thread should exit.

lf_sched_init()

void lf_sched_init	(	environment_t *	env,
		size_t	number_of_workers,
		sched_params_t *	params )

Initialize the scheduler.

This has to be called before other functions of the scheduler can be used. If the scheduler is already initialized, this will be a no-op.

Parameters

env	Environment within which we are executing.
number_of_workers	Indicate how many workers this scheduler will be managing.
option	Pointer to a sched_params_t struct containing additional scheduler parameters.

lf_scheduler_trigger_reaction()

void lf_scheduler_trigger_reaction	(	lf_scheduler_t *	scheduler,
		reaction_t *	reaction,
		int	worker_number )

Inform the scheduler that worker thread 'worker_number' would like to trigger 'reaction' at the current tag.

If a worker number is not available (e.g., this function is not called by a worker thread), -1 should be passed as the 'worker_number'.

The scheduler will ensure that the same reaction is not triggered twice in the same tag.

Parameters

scheduler	The scheduler
reaction	The reaction to trigger at the current tag.
worker_number	The ID of the worker that is making this call. 0 should be used if there is only one worker (e.g., when the program is using the single-threaded C runtime). -1 is used for an anonymous call in a context where a worker number does not make sense (e.g., the caller is not a worker thread).