StarPU Handbook
Workers’ Properties

Data Structures

struct  starpu_worker_collection
struct  starpu_sched_ctx_iterator


#define starpu_worker_get_id_check()


enum  starpu_node_kind {
enum  starpu_worker_archtype {
enum  starpu_worker_collection_type { STARPU_WORKER_TREE, STARPU_WORKER_LIST }


unsigned starpu_worker_get_count (void)
int starpu_worker_get_count_by_type (enum starpu_worker_archtype type)
unsigned starpu_cpu_worker_get_count (void)
unsigned starpu_cuda_worker_get_count (void)
unsigned starpu_mic_worker_get_count (void)
unsigned starpu_mic_device_get_count (void)
unsigned starpu_scc_worker_get_count (void)
unsigned starpu_opencl_worker_get_count (void)
int starpu_worker_get_id (void)
int starpu_worker_get_ids_by_type (enum starpu_worker_archtype type, int *workerids, int maxsize)
int starpu_worker_get_by_type (enum starpu_worker_archtype type, int num)
int starpu_worker_get_by_devid (enum starpu_worker_archtype type, int devid)
int starpu_worker_get_devid (int id)
enum starpu_worker_archtype starpu_worker_get_type (int id)
void starpu_worker_get_name (int id, char *dst, size_t maxlen)
unsigned starpu_worker_get_memory_node (unsigned workerid)
enum starpu_node_kind starpu_node_get_kind (unsigned node)
char * starpu_worker_get_type_as_string (enum starpu_worker_archtype type)

Detailed Description

Data Structure Documentation

◆ starpu_worker_collection

struct starpu_worker_collection

A scheduling context manages a collection of workers that can be memorized using different data structures. Thus, a generic structure is available in order to simplify the choice of its type. Only the list data structure is available but further data structures(like tree) implementations are foreseen.

Data Fields

int * workerids
void * collection_private
unsigned nworkers
void * masters
unsigned nmasters
char is_master [STARPU_NMAXWORKERS]
enum starpu_worker_collection_type type
unsigned(* has_next )(struct starpu_worker_collection *workers, struct starpu_sched_ctx_iterator *it)
int(* get_next )(struct starpu_worker_collection *workers, struct starpu_sched_ctx_iterator *it)
unsigned(* has_next_master )(struct starpu_worker_collection *workers, struct starpu_sched_ctx_iterator *it)
int(* get_next_master )(struct starpu_worker_collection *workers, struct starpu_sched_ctx_iterator *it)
int(* add )(struct starpu_worker_collection *workers, int worker)
int(* remove )(struct starpu_worker_collection *workers, int worker)
void(* init )(struct starpu_worker_collection *workers)
void(* deinit )(struct starpu_worker_collection *workers)
void(* init_iterator )(struct starpu_worker_collection *workers, struct starpu_sched_ctx_iterator *it)

Field Documentation

◆ workerids

void * starpu_worker_collection::workerids

The workerids managed by the collection

◆ nworkers

unsigned starpu_worker_collection::nworkers

The number of workers in the collection

◆ type

enum starpu_worker_collection_type starpu_worker_collection::type

The type of structure (currently STARPU_WORKER_LIST is the only one available)

◆ has_next

unsigned(* starpu_worker_collection::has_next)(struct starpu_worker_collection *workers, struct starpu_sched_ctx_iterator *it)

Checks if there is another element in collection

◆ get_next

int(* starpu_worker_collection::get_next)(struct starpu_worker_collection *workers, struct starpu_sched_ctx_iterator *it)

return the next element in the collection

◆ add

int(* starpu_worker_collection::add)(struct starpu_worker_collection *workers, int worker)

add a new element in the collection

◆ remove

int(* starpu_worker_collection::remove)(struct starpu_worker_collection *workers, int worker)

remove an element from the collection

◆ init

void(* starpu_worker_collection::init)(struct starpu_worker_collection *workers)

Initialize the collection

◆ deinit

void(* starpu_worker_collection::deinit)(struct starpu_worker_collection *workers)

Deinitialize the colection

◆ init_iterator

void(* starpu_worker_collection::init_iterator)(struct starpu_worker_collection *workers, struct starpu_sched_ctx_iterator *it)

Initialize the cursor if there is one

◆ starpu_sched_ctx_iterator

struct starpu_sched_ctx_iterator

Structure needed to iterate on the collection

Data Fields
int cursor

The index of the current worker in the collection, needed when iterating on the collection.

void * value
void * possible_value

Macro Definition Documentation



Define the maximum number of workers managed by StarPU.



Define the maximum number of CPU workers managed by StarPU. The default value can be modified at configure by using the option --enable-maxcpus.



Define the maximum number of memory nodes managed by StarPU. The default value can be modified at configure by using the option --enable-maxnodes. Reducing it allows to considerably reduce memory used by StarPU data structures.

◆ starpu_worker_get_id_check

unsigned starpu_worker_get_id_check ( )

This is the same as starpu_worker_get_id, but aborts when called from outside a worker (i.e. when starpu_worker_get_id() would return -1).

Enumeration Type Documentation

◆ starpu_node_kind













This node kind is not used anymore, but implementations in interfaces will be useful for MPI.



◆ starpu_worker_archtype

Worker Architecture Type


CPU core




OpenCL device


Intel MIC device


Intel SCC device


any worker, used in the hypervisor

◆ starpu_worker_collection_type

Types of structures the worker collection can implement


The collection is an array

Function Documentation

◆ starpu_worker_get_count()

unsigned starpu_worker_get_count ( void  )

This function returns the number of workers (i.e. processing units executing StarPU tasks). The returned value should be at most STARPU_NMAXWORKERS.

◆ starpu_worker_get_count_by_type()

int starpu_worker_get_count_by_type ( enum starpu_worker_archtype  type)

Returns the number of workers of the given type. A positive (or NULL) value is returned in case of success, -EINVAL indicates that the type is not valid otherwise.

◆ starpu_cpu_worker_get_count()

unsigned starpu_cpu_worker_get_count ( void  )

This function returns the number of CPUs controlled by StarPU. The returned value should be at most STARPU_MAXCPUS.

◆ starpu_cuda_worker_get_count()

unsigned starpu_cuda_worker_get_count ( void  )

This function returns the number of CUDA devices controlled by StarPU. The returned value should be at most STARPU_MAXCUDADEVS.

◆ starpu_mic_worker_get_count()

unsigned starpu_mic_worker_get_count ( void  )

This function returns the number of MIC workers controlled by StarPU.

◆ starpu_mic_device_get_count()

unsigned starpu_mic_device_get_count ( void  )

This function returns the number of MIC devices controlled by StarPU. The returned value should be at most STARPU_MAXMICDEVS.

◆ starpu_scc_worker_get_count()

unsigned starpu_scc_worker_get_count ( void  )

This function returns the number of SCC devices controlled by StarPU. The returned value should be at most STARPU_MAXSCCDEVS.

◆ starpu_opencl_worker_get_count()

unsigned starpu_opencl_worker_get_count ( void  )

This function returns the number of OpenCL devices controlled by StarPU. The returned value should be at most STARPU_MAXOPENCLDEVS.

◆ starpu_worker_get_id()

int starpu_worker_get_id ( void  )

This function returns the identifier of the current worker, i.e the one associated to the calling thread. The returned value is either -1 if the current context is not a StarPU worker (i.e. when called from the application outside a task or a callback), or an integer between 0 and starpu_worker_get_count() - 1.

◆ starpu_worker_get_ids_by_type()

int starpu_worker_get_ids_by_type ( enum starpu_worker_archtype  type,
int *  workerids,
int  maxsize 

This function gets the list of identifiers of workers with the given type. It fills the array workerids with the identifiers of the workers that have the type indicated in the first argument. The argument maxsize indicates the size of the array workerids. The returned value gives the number of identifiers that were put in the array. -ERANGE is returned is maxsize is lower than the number of workers with the appropriate type: in that case, the array is filled with the maxsize first elements. To avoid such overflows, the value of maxsize can be chosen by the means of the function starpu_worker_get_count_by_type(), or by passing a value greater or equal to STARPU_NMAXWORKERS.

◆ starpu_worker_get_by_type()

int starpu_worker_get_by_type ( enum starpu_worker_archtype  type,
int  num 

This returns the identifier of the num-th worker that has the specified type type. If there are no such worker, -1 is returned.

◆ starpu_worker_get_by_devid()

int starpu_worker_get_by_devid ( enum starpu_worker_archtype  type,
int  devid 

This returns the identifier of the worker that has the specified type type and device id devid (which may not be the n-th, if some devices are skipped for instance). If there are no such worker, -1 is returned.

◆ starpu_worker_get_devid()

int starpu_worker_get_devid ( int  id)

This function returns the device id of the given worker. The worker should be identified with the value returned by the starpu_worker_get_id() function. In the case of a CUDA worker, this device identifier is the logical device identifier exposed by CUDA (used by the function cudaGetDevice() for instance). The device identifier of a CPU worker is the logical identifier of the core on which the worker was bound; this identifier is either provided by the OS or by the library hwloc in case it is available.

◆ starpu_worker_get_type()

enum starpu_worker_archtype starpu_worker_get_type ( int  id)

This function returns the type of processing unit associated to a worker. The worker identifier is a value returned by the function starpu_worker_get_id()). The returned value indicates the architecture of the worker: STARPU_CPU_WORKER for a CPU core, STARPU_CUDA_WORKER for a CUDA device, and STARPU_OPENCL_WORKER for a OpenCL device. The value returned for an invalid identifier is unspecified.

◆ starpu_worker_get_name()

void starpu_worker_get_name ( int  id,
char *  dst,
size_t  maxlen 

This function allows to get the name of a given worker. StarPU associates a unique human readable string to each processing unit. This function copies at most the maxlen first bytes of the unique string associated to a worker identified by its identifier id into the dst buffer. The caller is responsible for ensuring that dst is a valid pointer to a buffer of maxlen bytes at least. Calling this function on an invalid identifier results in an unspecified behaviour.

◆ starpu_worker_get_memory_node()

unsigned starpu_worker_get_memory_node ( unsigned  workerid)

This function returns the identifier of the memory node associated to the worker identified by workerid.

◆ starpu_node_get_kind()

enum starpu_node_kind starpu_node_get_kind ( unsigned  node)

Returns the type of the given node as defined by starpu_node_kind. For example, when defining a new data interface, this function should be used in the allocation function to determine on which device the memory needs to be allocated.

◆ starpu_worker_get_type_as_string()

char * starpu_worker_get_type_as_string ( enum starpu_worker_archtype  type)

Returns the given worker type as a string.