StarPU Handbook
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...

Scheduling Contexts Basic API

void(*)(unsigned) starpu_sched_ctx_get_sched_policy_init (unsigned sched_ctx_id)
 
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, unsigned nworkers_ctx, unsigned sched_ctx_id)
 
void starpu_sched_ctx_remove_workers (int *workerids_ctx, unsigned 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)
 
unsigned starpu_sched_ctx_get_inheritor (unsigned sched_ctx_id)
 
unsigned starpu_sched_ctx_get_hierarchy_level (unsigned sched_ctx_id)
 
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_contains_type_of_worker (enum starpu_worker_archtype arch, unsigned sched_ctx_id)
 
unsigned starpu_sched_ctx_worker_get_id (unsigned sched_ctx_id)
 
unsigned starpu_sched_ctx_get_ctx_for_task (struct starpu_task *task)
 
unsigned starpu_sched_ctx_overlapping_ctxs_on_worker (int workerid)
 
void * starpu_sched_ctx_get_user_data (unsigned sched_ctx_id)
 
void starpu_sched_ctx_set_user_data (unsigned sched_ctx_id, void *user_data)
 
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)
 
struct starpu_sched_policystarpu_sched_ctx_get_sched_policy (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)
 
void starpu_sched_ctx_list_task_counters_increment (unsigned sched_ctx_id, int workerid)
 
void starpu_sched_ctx_list_task_counters_decrement (unsigned sched_ctx_id, int workerid)
 
void starpu_sched_ctx_list_task_counters_reset (unsigned sched_ctx_id, int workerid)
 
void starpu_sched_ctx_list_task_counters_increment_all_ctx_locked (struct starpu_task *task, unsigned sched_ctx_id)
 
void starpu_sched_ctx_list_task_counters_decrement_all_ctx_locked (struct starpu_task *task, unsigned sched_ctx_id)
 
void starpu_sched_ctx_list_task_counters_reset_all (struct starpu_task *task, unsigned sched_ctx_id)
 
void starpu_sched_ctx_set_priority (int *workers, int nworkers, unsigned sched_ctx_id, unsigned priority)
 
unsigned starpu_sched_ctx_get_priority (int worker, unsigned sched_ctx_id)
 
void starpu_sched_ctx_get_available_cpuids (unsigned sched_ctx_id, int **cpuids, int *ncpuids)
 
void starpu_sched_ctx_bind_current_thread_to_cpuid (unsigned cpuid)
 
int starpu_sched_ctx_book_workers_for_task (unsigned sched_ctx_id, int *workerids, int nworkers)
 
void starpu_sched_ctx_unbook_workers_for_task (unsigned sched_ctx_id, int master)
 
unsigned starpu_sched_ctx_worker_is_master_for_child_ctx (int workerid, unsigned sched_ctx_id)
 
unsigned starpu_sched_ctx_master_get_context (int masterid)
 
void starpu_sched_ctx_revert_task_counters_ctx_locked (unsigned sched_ctx_id, double flops)
 
void starpu_sched_ctx_move_task_to_ctx_locked (struct starpu_task *task, unsigned sched_ctx, unsigned with_repush)
 
int starpu_sched_ctx_get_worker_rank (unsigned sched_ctx_id)
 
unsigned starpu_sched_ctx_has_starpu_scheduler (unsigned sched_ctx_id, unsigned *awake_workers)
 
int starpu_sched_ctx_get_stream_worker (unsigned sub_ctx)
 
int starpu_sched_ctx_get_nsms (unsigned sched_ctx)
 
void starpu_sched_ctx_get_sms_interval (int stream_workerid, int *start, int *end)
 
#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
 
#define STARPU_SCHED_CTX_HIERARCHY_LEVEL
 
#define STARPU_SCHED_CTX_NESTED
 
#define STARPU_SCHED_CTX_AWAKE_WORKERS
 
#define STARPU_SCHED_CTX_POLICY_INIT
 
#define STARPU_SCHED_CTX_USER_DATA
 
#define STARPU_SCHED_CTX_CUDA_NSMS
 
#define STARPU_SCHED_CTX_SUB_CTXS
 

Scheduling Context Priorities

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_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_min_priority_is_set (unsigned sched_ctx_id)
 
int starpu_sched_ctx_max_priority_is_set (unsigned sched_ctx_id)
 
#define STARPU_MIN_PRIO
 
#define STARPU_MAX_PRIO
 
#define STARPU_DEFAULT_PRIO
 

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)
 

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.

Macro Definition Documentation

◆ STARPU_SCHED_CTX_POLICY_NAME

#define STARPU_SCHED_CTX_POLICY_NAME

Used when calling starpu_sched_ctx_create() to specify a name for a scheduling policy

◆ STARPU_SCHED_CTX_POLICY_STRUCT

#define STARPU_SCHED_CTX_POLICY_STRUCT

Used when calling starpu_sched_ctx_create() to specify a pointer to a scheduling policy

◆ STARPU_SCHED_CTX_POLICY_MIN_PRIO

#define STARPU_SCHED_CTX_POLICY_MIN_PRIO

Used when calling starpu_sched_ctx_create() to specify a minimum scheduler priority value.

◆ STARPU_SCHED_CTX_POLICY_MAX_PRIO

#define STARPU_SCHED_CTX_POLICY_MAX_PRIO

Used when calling starpu_sched_ctx_create() to specify a maximum scheduler priority value.

◆ STARPU_SCHED_CTX_AWAKE_WORKERS

#define STARPU_SCHED_CTX_AWAKE_WORKERS

Used when calling starpu_sched_ctx_create() to specify ???

◆ STARPU_SCHED_CTX_POLICY_INIT

#define STARPU_SCHED_CTX_POLICY_INIT

Used when calling starpu_sched_ctx_create() to specify a function pointer allowing to initialize the scheduling policy.

◆ STARPU_SCHED_CTX_USER_DATA

#define STARPU_SCHED_CTX_USER_DATA

Used when calling starpu_sched_ctx_create() to specify a pointer to some user data related to the context being created.

◆ STARPU_SCHED_CTX_CUDA_NSMS

#define STARPU_SCHED_CTX_CUDA_NSMS

Used when calling starpu_sched_ctx_create() in order to create a context on the NVIDIA GPU to specify the number of SMs the context should have

◆ STARPU_SCHED_CTX_SUB_CTXS

#define STARPU_SCHED_CTX_SUB_CTXS

Used when calling starpu_sched_ctx_create() to specify a list of sub contexts of the current context.

◆ STARPU_MIN_PRIO

#define STARPU_MIN_PRIO

Provided for legacy reasons.

◆ STARPU_MAX_PRIO

#define STARPU_MAX_PRIO

Provided for legacy reasons.

◆ STARPU_DEFAULT_PRIO

#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

◆ starpu_sched_ctx_create()

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

Create a scheduling context with the given parameters (see below) and assign 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:

◆ starpu_sched_ctx_create_inside_interval()

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

◆ starpu_sched_ctx_register_close_callback()

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 parameters sched_ctx and any other parameter needed by the application (packed in args)

◆ starpu_sched_ctx_add_workers()

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

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

◆ starpu_sched_ctx_remove_workers()

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

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

◆ starpu_sched_ctx_display_workers()

void starpu_sched_ctx_display_workers ( unsigned  sched_ctx_id,
FILE *  f 
)

Print on the file f the worker names belonging to the context sched_ctx_id

◆ starpu_sched_ctx_delete()

void starpu_sched_ctx_delete ( unsigned  sched_ctx_id)

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

◆ starpu_sched_ctx_set_inheritor()

void starpu_sched_ctx_set_inheritor ( unsigned  sched_ctx_id,
unsigned  inheritor 
)

Indicate that the context inheritor will inherit the resources of the context sched_ctx_id when sched_ctx_id will be deleted.

◆ starpu_sched_ctx_set_context()

void starpu_sched_ctx_set_context ( unsigned *  sched_ctx_id)

Set the scheduling context the subsequent tasks will be submitted to

◆ starpu_sched_ctx_get_context()

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().

◆ starpu_sched_ctx_stop_task_submission()

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

◆ starpu_sched_ctx_finished_submit()

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.

◆ starpu_sched_ctx_get_workers_list()

unsigned starpu_sched_ctx_get_workers_list ( unsigned  sched_ctx_id,
int **  workerids 
)

Return the list of workers in the array workerids, the return 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)

◆ starpu_sched_ctx_get_workers_list_raw()

unsigned starpu_sched_ctx_get_workers_list_raw ( unsigned  sched_ctx_id,
int **  workerids 
)

Return the list of workers in the array workerids, the return 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().

◆ starpu_sched_ctx_get_nworkers()

unsigned starpu_sched_ctx_get_nworkers ( unsigned  sched_ctx_id)

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

◆ starpu_sched_ctx_get_nshared_workers()

unsigned starpu_sched_ctx_get_nshared_workers ( unsigned  sched_ctx_id,
unsigned  sched_ctx_id2 
)

Return the number of workers shared by two contexts.

◆ starpu_sched_ctx_contains_worker()

unsigned starpu_sched_ctx_contains_worker ( int  workerid,
unsigned  sched_ctx_id 
)

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

◆ starpu_sched_ctx_worker_get_id()

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().

◆ starpu_sched_ctx_overlapping_ctxs_on_worker()

unsigned starpu_sched_ctx_overlapping_ctxs_on_worker ( int  workerid)

Check if a worker is shared between several contexts

◆ starpu_sched_ctx_get_user_data()

void* starpu_sched_ctx_get_user_data ( unsigned  sched_ctx_id)

Return the user data pointer associated to the scheduling context.

◆ starpu_sched_ctx_set_policy_data()

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

◆ starpu_sched_ctx_get_policy_data()

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.

◆ starpu_sched_ctx_exec_parallel_code()

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)

◆ starpu_sched_ctx_worker_is_master_for_child_ctx()

unsigned starpu_sched_ctx_worker_is_master_for_child_ctx ( int  workerid,
unsigned  sched_ctx_id 
)

Return the first context (child of sched_ctx_id) where the workerid is master

◆ starpu_sched_ctx_master_get_context()

unsigned starpu_sched_ctx_master_get_context ( int  masterid)

Return the context id of masterid if it master of a context. If not, return STARPU_NMAX_SCHED_CTXS.

◆ starpu_sched_ctx_get_min_priority()

int starpu_sched_ctx_get_min_priority ( unsigned  sched_ctx_id)

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

◆ starpu_sched_ctx_get_max_priority()

int starpu_sched_ctx_get_max_priority ( unsigned  sched_ctx_id)

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

◆ starpu_sched_ctx_set_min_priority()

int starpu_sched_ctx_set_min_priority ( unsigned  sched_ctx_id,
int  min_prio 
)

Define 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.

◆ starpu_sched_ctx_set_max_priority()

int starpu_sched_ctx_set_max_priority ( unsigned  sched_ctx_id,
int  max_prio 
)

Define 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.

◆ starpu_sched_ctx_create_worker_collection()

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

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

◆ starpu_sched_ctx_delete_worker_collection()

void starpu_sched_ctx_delete_worker_collection ( unsigned  sched_ctx_id)

Delete the worker collection of the specified scheduling context

◆ starpu_sched_ctx_get_worker_collection()

struct starpu_worker_collection* starpu_sched_ctx_get_worker_collection ( unsigned  sched_ctx_id)

Return the worker collection managed by the indicated context