StarPU Handbook
 All Data Structures Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
Scheduling Contexts

StarPU permits on one hand grouping workers in combined workers in order to execute a parallel task and on the other hand grouping tasks in bundles that will be executed by a single specified worker. In contrast when we group workers in scheduling contexts we submit starpu tasks to them and we schedule them with the policy assigned to the context. Scheduling contexts can be created, deleted and modified dynamically. More...

Data Structures

struct  starpu_sched_ctx_performance_counters

Scheduling Contexts Basic API

#define STARPU_SCHED_CTX_POLICY_NAME
#define STARPU_SCHED_CTX_POLICY_STRUCT
#define STARPU_SCHED_CTX_POLICY_MIN_PRIO
#define STARPU_SCHED_CTX_POLICY_MAX_PRIO
unsigned starpu_sched_ctx_create (int *workerids_ctx, int nworkers_ctx, const char *sched_ctx_name,...)
unsigned starpu_sched_ctx_create_inside_interval (const char *policy_name, const char *sched_ctx_name, int min_ncpus, int max_ncpus, int min_ngpus, int max_ngpus, unsigned allow_overlap)
void starpu_sched_ctx_register_close_callback (unsigned sched_ctx_id, void(*close_callback)(unsigned sched_ctx_id, void *args), void *args)
void starpu_sched_ctx_add_workers (int *workerids_ctx, int nworkers_ctx, unsigned sched_ctx_id)
void starpu_sched_ctx_remove_workers (int *workerids_ctx, int nworkers_ctx, unsigned sched_ctx_id)
void starpu_sched_ctx_display_workers (unsigned sched_ctx_id, FILE *f)
void starpu_sched_ctx_delete (unsigned sched_ctx_id)
void starpu_sched_ctx_set_inheritor (unsigned sched_ctx_id, unsigned inheritor)
void starpu_sched_ctx_set_context (unsigned *sched_ctx_id)
unsigned starpu_sched_ctx_get_context (void)
void starpu_sched_ctx_stop_task_submission (void)
void starpu_sched_ctx_finished_submit (unsigned sched_ctx_id)
unsigned starpu_sched_ctx_get_workers_list (unsigned sched_ctx_id, int **workerids)
unsigned starpu_sched_ctx_get_workers_list_raw (unsigned sched_ctx_id, int **workerids)
unsigned starpu_sched_ctx_get_nworkers (unsigned sched_ctx_id)
unsigned starpu_sched_ctx_get_nshared_workers (unsigned sched_ctx_id, unsigned sched_ctx_id2)
unsigned starpu_sched_ctx_contains_worker (int workerid, unsigned sched_ctx_id)
unsigned starpu_sched_ctx_worker_get_id (unsigned sched_ctx_id)
unsigned starpu_sched_ctx_overlapping_ctxs_on_worker (int workerid)

Scheduling Context Priorities

#define STARPU_MIN_PRIO
#define STARPU_MAX_PRIO
#define STARPU_DEFAULT_PRIO
int starpu_sched_ctx_set_min_priority (unsigned sched_ctx_id, int min_prio)
int starpu_sched_ctx_set_max_priority (unsigned sched_ctx_id, int max_prio)
int starpu_sched_ctx_get_min_priority (unsigned sched_ctx_id)
int starpu_sched_ctx_get_max_priority (unsigned sched_ctx_id)
int starpu_sched_ctx_min_priority_is_set (unsigned sched_ctx_id)
int starpu_sched_ctx_max_priority_is_set (unsigned sched_ctx_id)

Scheduling Context Worker Collection

struct starpu_worker_collectionstarpu_sched_ctx_create_worker_collection (unsigned sched_ctx_id, enum starpu_worker_collection_type type) STARPU_ATTRIBUTE_MALLOC
void starpu_sched_ctx_delete_worker_collection (unsigned sched_ctx_id)
struct starpu_worker_collectionstarpu_sched_ctx_get_worker_collection (unsigned sched_ctx_id)

Scheduling Context Link with Hypervisor

void starpu_sched_ctx_set_perf_counters (unsigned sched_ctx_id, void *perf_counters)
void starpu_sched_ctx_call_pushed_task_cb (int workerid, unsigned sched_ctx_id)
void starpu_sched_ctx_notify_hypervisor_exists (void)
unsigned starpu_sched_ctx_check_if_hypervisor_exists (void)
void starpu_sched_ctx_set_policy_data (unsigned sched_ctx_id, void *policy_data)
void * starpu_sched_ctx_get_policy_data (unsigned sched_ctx_id)
void * starpu_sched_ctx_exec_parallel_code (void *(*func)(void *), void *param, unsigned sched_ctx_id)
int starpu_sched_ctx_get_nready_tasks (unsigned sched_ctx_id)
double starpu_sched_ctx_get_nready_flops (unsigned sched_ctx_id)

Detailed Description

StarPU permits on one hand grouping workers in combined workers in order to execute a parallel task and on the other hand grouping tasks in bundles that will be executed by a single specified worker. In contrast when we group workers in scheduling contexts we submit starpu tasks to them and we schedule them with the policy assigned to the context. Scheduling contexts can be created, deleted and modified dynamically.


Data Structure Documentation

struct starpu_sched_ctx_performance_counters

Performance counters used by the starpu to indicate the hypervisor how the application and the resources are executing.

Data Fields

void(* notify_idle_cycle )(unsigned sched_ctx_id, int worker, double idle_time)
void(* notify_poped_task )(unsigned sched_ctx_id, int worker)
void(* notify_pushed_task )(unsigned sched_ctx_id, int worker)
void(* notify_post_exec_task )(struct starpu_task *task, size_t data_size, uint32_t footprint, int hypervisor_tag, double flops)
void(* notify_submitted_job )(struct starpu_task *task, uint32_t footprint, size_t data_size)
void(* notify_empty_ctx )(unsigned sched_ctx_id, struct starpu_task *task)
void(* notify_delete_context )(unsigned sched_ctx)

Field Documentation

void(* starpu_sched_ctx_performance_counters::notify_idle_cycle)(unsigned sched_ctx_id, int worker, double idle_time)

Informs the hypervisor for how long a worker has been idle in the specified context

void(* starpu_sched_ctx_performance_counters::notify_poped_task)(unsigned sched_ctx_id, int worker)

Informs the hypervisor that a task executing a specified number of instructions has been poped from the worker

void(* starpu_sched_ctx_performance_counters::notify_pushed_task)(unsigned sched_ctx_id, int worker)

Notifies the hypervisor that a task has been scheduled on the queue of the worker corresponding to the specified context

void(* starpu_sched_ctx_performance_counters::notify_post_exec_task)(struct starpu_task *task, size_t data_size, uint32_t footprint, int hypervisor_tag, double flops)

Notifies the hypervisor that a task has just been executed

void(* starpu_sched_ctx_performance_counters::notify_submitted_job)(struct starpu_task *task, uint32_t footprint, size_t data_size)

Notifies the hypervisor that a task has just been submitted

void(* starpu_sched_ctx_performance_counters::notify_delete_context)(unsigned sched_ctx)

Notifies the hypervisor that the context was deleted

Macro Definition Documentation

#define STARPU_SCHED_CTX_POLICY_NAME

This macro is used when calling starpu_sched_ctx_create() to specify a name for a scheduling policy

#define STARPU_SCHED_CTX_POLICY_STRUCT

This macro is used when calling starpu_sched_ctx_create() to specify a pointer to a scheduling policy

#define STARPU_SCHED_CTX_POLICY_MIN_PRIO

This macro is used when calling starpu_sched_ctx_create() to specify a minimum scheduler priority value.

#define STARPU_SCHED_CTX_POLICY_MAX_PRIO

This macro is used when calling starpu_sched_ctx_create() to specify a maximum scheduler priority value.

#define STARPU_MIN_PRIO

Provided for legacy reasons.

#define STARPU_MAX_PRIO

Provided for legacy reasons.

#define STARPU_DEFAULT_PRIO

By convention, the default priority level should be 0 so that we can statically allocate tasks with a default priority.

Function Documentation

unsigned starpu_sched_ctx_create ( int *  workerids_ctx,
int  nworkers_ctx,
const char *  sched_ctx_name,
  ... 
)

This function creates a scheduling context with the given parameters (see below) and assigns the workers in workerids_ctx to execute the tasks submitted to it. The return value represents the identifier of the context that has just been created. It will be further used to indicate the context the tasks will be submitted to. The return value should be at most STARPU_NMAX_SCHED_CTXS.

The arguments following the name of the scheduling context can be of the following types:

unsigned starpu_sched_ctx_create_inside_interval ( const char *  policy_name,
const char *  sched_ctx_name,
int  min_ncpus,
int  max_ncpus,
int  min_ngpus,
int  max_ngpus,
unsigned  allow_overlap 
)

Create a context indicating an approximate interval of resources

void starpu_sched_ctx_register_close_callback ( unsigned  sched_ctx_id,
void(*)(unsigned sched_ctx_id, void *args)  close_callback,
void *  args 
)

Execute the callback whenever the last task of the context finished executing, it is called with the pramaters: sched_ctx and any other paramter needed by the application (packed in a void*)

void starpu_sched_ctx_add_workers ( int *  workerids_ctx,
int  nworkers_ctx,
unsigned  sched_ctx_id 
)

This function adds dynamically the workers in workerids_ctx to the context sched_ctx_id. The last argument cannot be greater than STARPU_NMAX_SCHED_CTXS.

void starpu_sched_ctx_remove_workers ( int *  workerids_ctx,
int  nworkers_ctx,
unsigned  sched_ctx_id 
)

This function removes the workers in workerids_ctx from the context sched_ctx_id. The last argument cannot be greater than STARPU_NMAX_SCHED_CTXS.

void starpu_sched_ctx_display_workers ( unsigned  sched_ctx_id,
FILE *  f 
)

This function prints on the file f the worker names belonging to the context sched_ctx_id

void starpu_sched_ctx_delete ( unsigned  sched_ctx_id)

Delete scheduling context sched_ctx_id and transfer remaining workers to the inheritor scheduling context.

void starpu_sched_ctx_set_inheritor ( unsigned  sched_ctx_id,
unsigned  inheritor 
)

Indicate which context whill inherit the resources of this context when he will be deleted.

void starpu_sched_ctx_set_context ( unsigned *  sched_ctx_id)

Set the scheduling context the subsequent tasks will be submitted to

unsigned starpu_sched_ctx_get_context ( void  )

Return the scheduling context the tasks are currently submitted to, or STARPU_NMAX_SCHED_CTXS if no default context has been defined by calling the function starpu_sched_ctx_set_context().

void starpu_sched_ctx_stop_task_submission ( void  )

Stop submitting tasks from the empty context list until the next time the context has time to check the empty context list

void starpu_sched_ctx_finished_submit ( unsigned  sched_ctx_id)

Indicate starpu that the application finished submitting to this context in order to move the workers to the inheritor as soon as possible.

unsigned starpu_sched_ctx_get_workers_list ( unsigned  sched_ctx_id,
int **  workerids 
)

Returns the list of workers in the array workerids, the returned value is the number of workers. The user should free the workerids table after finishing using it (it is allocated inside the function with the proper size)

unsigned starpu_sched_ctx_get_workers_list_raw ( unsigned  sched_ctx_id,
int **  workerids 
)

Returns the list of workers in the array workerids, the returned value is the number of workers. This list is provided in raw order, i.e. not sorted by tree or list order, and the user should not free the workerids table. This function is thus much less costly than starpu_sched_ctx_get_workers_list.

unsigned starpu_sched_ctx_get_nworkers ( unsigned  sched_ctx_id)

Return the number of workers managed by the specified contexts (Usually needed to verify if it manages any workers or if it should be blocked)

unsigned starpu_sched_ctx_get_nshared_workers ( unsigned  sched_ctx_id,
unsigned  sched_ctx_id2 
)

Return the number of workers shared by two contexts.

unsigned starpu_sched_ctx_contains_worker ( int  workerid,
unsigned  sched_ctx_id 
)

Return 1 if the worker belongs to the context and 0 otherwise

unsigned starpu_sched_ctx_worker_get_id ( unsigned  sched_ctx_id)

Return the workerid if the worker belongs to the context and -1 otherwise. If the thread calling this function is not a worker the function returns -1 as it calls the function starpu_worker_get_id().

unsigned starpu_sched_ctx_overlapping_ctxs_on_worker ( int  workerid)

Check if a worker is shared between several contexts

int starpu_sched_ctx_set_min_priority ( unsigned  sched_ctx_id,
int  min_prio 
)

Defines the minimum task priority level supported by the scheduling policy of the given scheduler context. The default minimum priority level is the same as the default priority level which is 0 by convention. The application may access that value by calling the function starpu_sched_ctx_get_min_priority(). This function should only be called from the initialization method of the scheduling policy, and should not be used directly from the application.

int starpu_sched_ctx_set_max_priority ( unsigned  sched_ctx_id,
int  max_prio 
)

Defines the maximum priority level supported by the scheduling policy of the given scheduler context. The default maximum priority level is 1. The application may access that value by calling the starpu_sched_ctx_get_max_priority function. This function should only be called from the initialization method of the scheduling policy, and should not be used directly from the application.

int starpu_sched_ctx_get_min_priority ( unsigned  sched_ctx_id)

Returns the current minimum priority level supported by the scheduling policy of the given scheduler context.

int starpu_sched_ctx_get_max_priority ( unsigned  sched_ctx_id)

Returns the current maximum priority level supported by the scheduling policy of the given scheduler context.

int starpu_sched_ctx_min_priority_is_set ( unsigned  sched_ctx_id)

todo

int starpu_sched_ctx_max_priority_is_set ( unsigned  sched_ctx_id)

todo

struct starpu_worker_collection * starpu_sched_ctx_create_worker_collection ( unsigned  sched_ctx_id,
enum starpu_worker_collection_type  type 
)
read

Create a worker collection of the type indicated by the last parameter for the context specified through the first parameter.

void starpu_sched_ctx_delete_worker_collection ( unsigned  sched_ctx_id)

Delete the worker collection of the specified scheduling context

struct starpu_worker_collection * starpu_sched_ctx_get_worker_collection ( unsigned  sched_ctx_id)
read

Return the worker collection managed by the indicated context

void starpu_sched_ctx_set_perf_counters ( unsigned  sched_ctx_id,
void *  perf_counters 
)

Indicates to starpu the pointer to the performance counter

void starpu_sched_ctx_call_pushed_task_cb ( int  workerid,
unsigned  sched_ctx_id 
)

Callback that lets the scheduling policy tell the hypervisor that a task was pushed on a worker

void starpu_sched_ctx_notify_hypervisor_exists ( void  )

Allow the hypervisor to let starpu know he's initialised

unsigned starpu_sched_ctx_check_if_hypervisor_exists ( void  )

Ask starpu if he is informed if the hypervisor is initialised

void starpu_sched_ctx_set_policy_data ( unsigned  sched_ctx_id,
void *  policy_data 
)

Allocate the scheduling policy data (private information of the scheduler like queues, variables, additional condition variables) the context

void * starpu_sched_ctx_get_policy_data ( unsigned  sched_ctx_id)

Return the scheduling policy data (private information of the scheduler) of the contexts previously assigned to.

void * starpu_sched_ctx_exec_parallel_code ( void *(*)(void *)  func,
void *  param,
unsigned  sched_ctx_id 
)

execute any parallel code on the workers of the sched_ctx (workers are blocked)

int starpu_sched_ctx_get_nready_tasks ( unsigned  sched_ctx_id)

todo

double starpu_sched_ctx_get_nready_flops ( unsigned  sched_ctx_id)

todo