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Data Partition

Data Structures

struct  starpu_data_filter

Basic API

void starpu_data_partition (starpu_data_handle_t initial_handle, struct starpu_data_filter *f)
void starpu_data_unpartition (starpu_data_handle_t root_data, unsigned gathering_node)
int starpu_data_get_nb_children (starpu_data_handle_t handle)
starpu_data_handle_t starpu_data_get_child (starpu_data_handle_t handle, unsigned i)
starpu_data_handle_t starpu_data_get_sub_data (starpu_data_handle_t root_data, unsigned depth,...)
starpu_data_handle_t starpu_data_vget_sub_data (starpu_data_handle_t root_data, unsigned depth, va_list pa)
void starpu_data_map_filters (starpu_data_handle_t root_data, unsigned nfilters,...)
void starpu_data_vmap_filters (starpu_data_handle_t root_data, unsigned nfilters, va_list pa)

Asynchronous API

void starpu_data_partition_plan (starpu_data_handle_t initial_handle, struct starpu_data_filter *f, starpu_data_handle_t *children)
void starpu_data_partition_submit (starpu_data_handle_t initial_handle, unsigned nparts, starpu_data_handle_t *children)
void starpu_data_partition_readonly_submit (starpu_data_handle_t initial_handle, unsigned nparts, starpu_data_handle_t *children)
void starpu_data_partition_readwrite_upgrade_submit (starpu_data_handle_t initial_handle, unsigned nparts, starpu_data_handle_t *children)
void starpu_data_unpartition_submit (starpu_data_handle_t initial_handle, unsigned nparts, starpu_data_handle_t *children, int gathering_node)
void starpu_data_unpartition_readonly_submit (starpu_data_handle_t initial_handle, unsigned nparts, starpu_data_handle_t *children, int gathering_node)
void starpu_data_partition_clean (starpu_data_handle_t root_data, unsigned nparts, starpu_data_handle_t *children)

Predefined Vector Filter Functions

This section gives a partial list of the predefined partitioning functions for vector data. Examples on how to use them are shown in Partitioning Data. The complete list can be found in the file starpu_data_filters.h.

void starpu_vector_filter_block (void *father_interface, void *child_interface, struct starpu_data_filter *f, unsigned id, unsigned nparts)
void starpu_vector_filter_block_shadow (void *father_interface, void *child_interface, struct starpu_data_filter *f, unsigned id, unsigned nparts)
void starpu_vector_filter_list (void *father_interface, void *child_interface, struct starpu_data_filter *f, unsigned id, unsigned nparts)
void starpu_vector_filter_divide_in_2 (void *father_interface, void *child_interface, struct starpu_data_filter *f, unsigned id, unsigned nparts)

Predefined Matrix Filter Functions

This section gives a partial list of the predefined partitioning functions for matrix data. Examples on how to use them are shown in Partitioning Data. The complete list can be found in the file starpu_data_filters.h.

void starpu_matrix_filter_block (void *father_interface, void *child_interface, struct starpu_data_filter *f, unsigned id, unsigned nparts)
void starpu_matrix_filter_block_shadow (void *father_interface, void *child_interface, struct starpu_data_filter *f, unsigned id, unsigned nparts)
void starpu_matrix_filter_vertical_block (void *father_interface, void *child_interface, struct starpu_data_filter *f, unsigned id, unsigned nparts)
void starpu_matrix_filter_vertical_block_shadow (void *father_interface, void *child_interface, struct starpu_data_filter *f, unsigned id, unsigned nparts)

Predefined Block Filter Functions

This section gives a partial list of the predefined partitioning functions for block data. Examples on how to use them are shown in Partitioning Data. The complete list can be found in the file starpu_data_filters.h. A usage example is available in examples/filters/shadow3d.c

void starpu_block_filter_block (void *father_interface, void *child_interface, struct starpu_data_filter *f, unsigned id, unsigned nparts)
void starpu_block_filter_block_shadow (void *father_interface, void *child_interface, struct starpu_data_filter *f, unsigned id, unsigned nparts)
void starpu_block_filter_vertical_block (void *father_interface, void *child_interface, struct starpu_data_filter *f, unsigned id, unsigned nparts)
void starpu_block_filter_vertical_block_shadow (void *father_interface, void *child_interface, struct starpu_data_filter *f, unsigned id, unsigned nparts)
void starpu_block_filter_depth_block (void *father_interface, void *child_interface, struct starpu_data_filter *f, unsigned id, unsigned nparts)
void starpu_block_filter_depth_block_shadow (void *father_interface, void *child_interface, struct starpu_data_filter *f, unsigned id, unsigned nparts)

Predefined BCSR Filter Functions

This section gives a partial list of the predefined partitioning functions for BCSR data. Examples on how to use them are shown in Partitioning Data. The complete list can be found in the file starpu_data_filters.h.

void starpu_bcsr_filter_canonical_block (void *father_interface, void *child_interface, struct starpu_data_filter *f, unsigned id, unsigned nparts)
void starpu_csr_filter_vertical_block (void *father_interface, void *child_interface, struct starpu_data_filter *f, unsigned id, unsigned nparts)

Detailed Description


Data Structure Documentation

struct starpu_data_filter

The filter structure describes a data partitioning operation, to be given to the starpu_data_partition() function.

Data Fields

void(* filter_func )(void *father_interface, void *child_interface, struct starpu_data_filter *, unsigned id, unsigned nparts)
unsigned nchildren
unsigned(* get_nchildren )(struct starpu_data_filter *, starpu_data_handle_t initial_handle)
struct
starpu_data_interface_ops *(* 
get_child_ops )(struct starpu_data_filter *, unsigned id)
unsigned filter_arg
void * filter_arg_ptr

Field Documentation

void(* starpu_data_filter::filter_func)(void *father_interface, void *child_interface, struct starpu_data_filter *, unsigned id, unsigned nparts)

This function fills the child_interface structure with interface information for the id-th child of the parent father_interface (among nparts).

unsigned starpu_data_filter::nchildren

This is the number of parts to partition the data into.

unsigned(* starpu_data_filter::get_nchildren)(struct starpu_data_filter *, starpu_data_handle_t initial_handle)

This returns the number of children. This can be used instead of nchildren when the number of children depends on the actual data (e.g. the number of blocks in a sparse matrix).

struct starpu_data_interface_ops *(* starpu_data_filter::get_child_ops)(struct starpu_data_filter *, unsigned id)
read

In case the resulting children use a different data interface, this function returns which interface is used by child number id.

unsigned starpu_data_filter::filter_arg

Allow to define an additional parameter for the filter function.

void * starpu_data_filter::filter_arg_ptr

Allow to define an additional pointer parameter for the filter function, such as the sizes of the different parts.

Function Documentation

void starpu_data_partition ( starpu_data_handle_t  initial_handle,
struct starpu_data_filter f 
)

This requests partitioning one StarPU data initial_handle into several subdata according to the filter f.

Here an example of how to use the function.

struct starpu_data_filter f = {
.nchildren = nslicesx
};
starpu_data_partition(A_handle, &f);
void starpu_data_unpartition ( starpu_data_handle_t  root_data,
unsigned  gathering_node 
)

This unapplies one filter, thus unpartitioning the data. The pieces of data are collected back into one big piece in the gathering_node (usually STARPU_MAIN_RAM). Tasks working on the partitioned data must be already finished when calling starpu_data_unpartition().

Here an example of how to use the function.

int starpu_data_get_nb_children ( starpu_data_handle_t  handle)

This function returns the number of children.

starpu_data_handle_t starpu_data_get_child ( starpu_data_handle_t  handle,
unsigned  i 
)

Return the ith child of the given handle, which must have been partitionned beforehand.

starpu_data_handle_t starpu_data_get_sub_data ( starpu_data_handle_t  root_data,
unsigned  depth,
  ... 
)

After partitioning a StarPU data by applying a filter, starpu_data_get_sub_data() can be used to get handles for each of the data portions. root_data is the parent data that was partitioned. depth is the number of filters to traverse (in case several filters have been applied, to e.g. partition in row blocks, and then in column blocks), and the subsequent parameters are the indexes. The function returns a handle to the subdata.

Here an example of how to use the function.

h = starpu_data_get_sub_data(A_handle, 1, taskx);
starpu_data_handle_t starpu_data_vget_sub_data ( starpu_data_handle_t  root_data,
unsigned  depth,
va_list  pa 
)

This function is similar to starpu_data_get_sub_data() but uses a va_list for the parameter list.

void starpu_data_map_filters ( starpu_data_handle_t  root_data,
unsigned  nfilters,
  ... 
)

Applies nfilters filters to the handle designated by root_handle recursively. nfilters pointers to variables of the type starpu_data_filter should be given.

void starpu_data_vmap_filters ( starpu_data_handle_t  root_data,
unsigned  nfilters,
va_list  pa 
)

Applies nfilters filters to the handle designated by root_handle recursively. It uses a va_list of pointers to variables of the type starpu_data_filter.

void starpu_data_partition_plan ( starpu_data_handle_t  initial_handle,
struct starpu_data_filter f,
starpu_data_handle_t children 
)

This plans for partitioning one StarPU data handle initial_handle into several subdata according to the filter f. The handles are returned into the children array, which has to be the same size as the number of parts described in f. These handles are not immediately usable, starpu_data_partition_submit has to be called to submit the actual partitioning.

Here is an example of how to use the function:

starpu_data_handle_t children[nslicesx];
struct starpu_data_filter f = {
.nchildren = nslicesx
};
starpu_data_partition_plan(A_handle, &f, children);
void starpu_data_partition_submit ( starpu_data_handle_t  initial_handle,
unsigned  nparts,
starpu_data_handle_t children 
)

This submits the actual partitioning of initial_handle into the nparts children handles. This call is asynchronous, it only submits that the partitioning should be done, so that the children handles can now be used to submit tasks, and initial_handle can not be used to submit tasks any more (to guarantee coherency).

For instance,

starpu_data_partition_submit(A_handle, nslicesx, children);
void starpu_data_partition_readonly_submit ( starpu_data_handle_t  initial_handle,
unsigned  nparts,
starpu_data_handle_t children 
)

This is the same as starpu_data_partition_submit, but does not invalidate initial_handle. This allows to continue using it, but the application has to be careful not to write to initial_handle or children handles, only read from them, since the coherency is otherwise not guaranteed. This thus allows to submit various tasks which concurrently read from various partitions of the data.

When the application wants to write to initial_handle again, it should call starpu_data_unpartition_submit, which will properly add dependencies between the reads on the children and the writes to be submitted.

If instead the application wants to write to children handles, it should call starpu_data_partition_readwrite_upgrade_submit, which will properly add dependencies between the reads on the initial_handle and the writes to be submitted.

void starpu_data_partition_readwrite_upgrade_submit ( starpu_data_handle_t  initial_handle,
unsigned  nparts,
starpu_data_handle_t children 
)

This assumes that a partitioning of initial_handle has already been submited in readonly mode through starpu_data_partition_readonly_submit, and will upgrade that partitioning into read-write mode for the children, by invalidating initial_handle, and adding the necessary dependencies.

void starpu_data_unpartition_submit ( starpu_data_handle_t  initial_handle,
unsigned  nparts,
starpu_data_handle_t children,
int  gathering_node 
)

This assumes that initial_handle is partitioned into children, and submits an unpartitionning of it, i.e. submitting a gathering of the pieces on the requested gathering_node memory node, and submitting an invalidation of the children.

gathering_node can be set to -1 to let the runtime decide which memory node should be used to gather the pieces.

void starpu_data_unpartition_readonly_submit ( starpu_data_handle_t  initial_handle,
unsigned  nparts,
starpu_data_handle_t children,
int  gathering_node 
)

This assumes that initial_handle is partitioned into children, and submits just a readonly unpartitionning of it, i.e. submitting a gathering of the pieces on the requested gathering_node memory node. It does not invalidate the children. This brings initial_handle and children handles to the same state as obtained with starpu_data_partition_readonly_submit.

gathering_node can be set to -1 to let the runtime decide which memory node should be used to gather the pieces.

void starpu_data_partition_clean ( starpu_data_handle_t  root_data,
unsigned  nparts,
starpu_data_handle_t children 
)

This should be used to clear the partition planning established between root_data and children with starpu_data_partition_plan. This will notably submit an unregister all the children, which can thus not be used any more afterwards.

void starpu_vector_filter_block ( void *  father_interface,
void *  child_interface,
struct starpu_data_filter f,
unsigned  id,
unsigned  nparts 
)

Return in child_interface the id th element of the vector represented by father_interface once partitioned in nparts chunks of equal size.

void starpu_vector_filter_block_shadow ( void *  father_interface,
void *  child_interface,
struct starpu_data_filter f,
unsigned  id,
unsigned  nparts 
)

Return in child_interface the id th element of the vector represented by father_interface once partitioned in nparts chunks of equal size with a shadow border filter_arg_ptr, thus getting a vector of size (n-2*shadow)/nparts+2*shadow. The filter_arg_ptr field of f must be the shadow size casted into void*. IMPORTANT: This can only be used for read-only access, as no coherency is enforced for the shadowed parts. An usage example is available in examples/filters/shadow.c

void starpu_vector_filter_list ( void *  father_interface,
void *  child_interface,
struct starpu_data_filter f,
unsigned  id,
unsigned  nparts 
)

Return in child_interface the id th element of the vector represented by father_interface once partitioned into nparts chunks according to the filter_arg_ptr field of f. The filter_arg_ptr field must point to an array of nparts uint32_t elements, each of which specifies the number of elements in each chunk of the partition.

void starpu_vector_filter_divide_in_2 ( void *  father_interface,
void *  child_interface,
struct starpu_data_filter f,
unsigned  id,
unsigned  nparts 
)

Return in child_interface the id th element of the vector represented by father_interface once partitioned in 2 chunks of equal size, ignoring nparts. Thus, id must be 0 or 1.

void starpu_matrix_filter_block ( void *  father_interface,
void *  child_interface,
struct starpu_data_filter f,
unsigned  id,
unsigned  nparts 
)

This partitions a dense Matrix along the x dimension, thus getting (x/nparts ,y) matrices. If nparts does not divide x, the last submatrix contains the remainder.

void starpu_matrix_filter_block_shadow ( void *  father_interface,
void *  child_interface,
struct starpu_data_filter f,
unsigned  id,
unsigned  nparts 
)

This partitions a dense Matrix along the x dimension, with a shadow border filter_arg_ptr, thus getting ((x-2*shadow)/nparts +2*shadow,y) matrices. If nparts does not divide x-2*shadow, the last submatrix contains the remainder. IMPORTANT: This can only be used for read-only access, as no coherency is enforced for the shadowed parts. A usage example is available in examples/filters/shadow2d.c

void starpu_matrix_filter_vertical_block ( void *  father_interface,
void *  child_interface,
struct starpu_data_filter f,
unsigned  id,
unsigned  nparts 
)

This partitions a dense Matrix along the y dimension, thus getting (x,y/nparts) matrices. If nparts does not divide y, the last submatrix contains the remainder.

void starpu_matrix_filter_vertical_block_shadow ( void *  father_interface,
void *  child_interface,
struct starpu_data_filter f,
unsigned  id,
unsigned  nparts 
)

This partitions a dense Matrix along the y dimension, with a shadow border filter_arg_ptr, thus getting (x,(y-2*shadow)/nparts +2*shadow) matrices. If nparts does not divide y-2*shadow, the last submatrix contains the remainder. IMPORTANT: This can only be used for read-only access, as no coherency is enforced for the shadowed parts. A usage example is available in examples/filters/shadow2d.c

void starpu_block_filter_block ( void *  father_interface,
void *  child_interface,
struct starpu_data_filter f,
unsigned  id,
unsigned  nparts 
)

This partitions a block along the X dimension, thus getting (x/nparts ,y,z) 3D matrices. If nparts does not divide x, the last submatrix contains the remainder.

void starpu_block_filter_block_shadow ( void *  father_interface,
void *  child_interface,
struct starpu_data_filter f,
unsigned  id,
unsigned  nparts 
)

This partitions a block along the X dimension, with a shadow border filter_arg_ptr, thus getting ((x-2*shadow)/nparts +2*shadow,y,z) blocks. If nparts does not divide x, the last submatrix contains the remainder. IMPORTANT: This can only be used for read-only access, as no coherency is enforced for the shadowed parts.

void starpu_block_filter_vertical_block ( void *  father_interface,
void *  child_interface,
struct starpu_data_filter f,
unsigned  id,
unsigned  nparts 
)

This partitions a block along the Y dimension, thus getting (x,y/nparts ,z) blocks. If nparts does not divide y, the last submatrix contains the remainder.

void starpu_block_filter_vertical_block_shadow ( void *  father_interface,
void *  child_interface,
struct starpu_data_filter f,
unsigned  id,
unsigned  nparts 
)

This partitions a block along the Y dimension, with a shadow border filter_arg_ptr, thus getting (x,(y-2*shadow)/nparts +2*shadow,z) 3D matrices. If nparts does not divide y, the last submatrix contains the remainder. IMPORTANT: This can only be used for read-only access, as no coherency is enforced for the shadowed parts.

void starpu_block_filter_depth_block ( void *  father_interface,
void *  child_interface,
struct starpu_data_filter f,
unsigned  id,
unsigned  nparts 
)

This partitions a block along the Z dimension, thus getting (x,y,z/nparts) blocks. If nparts does not divide z, the last submatrix contains the remainder.

void starpu_block_filter_depth_block_shadow ( void *  father_interface,
void *  child_interface,
struct starpu_data_filter f,
unsigned  id,
unsigned  nparts 
)

This partitions a block along the Z dimension, with a shadow border filter_arg_ptr, thus getting (x,y,(z-2*shadow)/nparts +2*shadow) blocks. If nparts does not divide z, the last submatrix contains the remainder. IMPORTANT: This can only be used for read-only access, as no coherency is enforced for the shadowed parts.

void starpu_bcsr_filter_canonical_block ( void *  father_interface,
void *  child_interface,
struct starpu_data_filter f,
unsigned  id,
unsigned  nparts 
)

This partitions a block-sparse matrix into dense matrices.

void starpu_csr_filter_vertical_block ( void *  father_interface,
void *  child_interface,
struct starpu_data_filter f,
unsigned  id,
unsigned  nparts 
)

This partitions a block-sparse matrix into vertical block-sparse matrices.