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@@ -226,7 +226,6 @@ static struct starpu_data_interface_ops interface_complex_ops =
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@end smallexample
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@end cartouche
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-@page
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@node MPI Insert Task Utility
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@section MPI Insert Task Utility
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@@ -239,90 +238,14 @@ exchange the content of the handle. All MPI nodes then process the whole task
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graph, and StarPU automatically determines which node actually execute which
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task, and trigger the required MPI transfers.
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-@deftypefun int starpu_data_set_tag (starpu_data_handle_t @var{handle}, int @var{tag})
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-Tell StarPU-MPI which MPI tag to use when exchanging the data.
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-@end deftypefun
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-
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-@deftypefun int starpu_data_get_tag (starpu_data_handle_t @var{handle})
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-Returns the MPI tag to be used when exchanging the data.
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-@end deftypefun
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-
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-@deftypefun int starpu_data_set_rank (starpu_data_handle_t @var{handle}, int @var{rank})
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-Tell StarPU-MPI which MPI node "owns" a given data, that is, the node which will
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-always keep an up-to-date value, and will by default execute tasks which write
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-to it.
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-@end deftypefun
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-
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-@deftypefun int starpu_data_get_rank (starpu_data_handle_t @var{handle})
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-Returns the last value set by @code{starpu_data_set_rank}.
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-@end deftypefun
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-
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-@defmac STARPU_EXECUTE_ON_NODE
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-this macro is used when calling @code{starpu_mpi_insert_task}, and
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-must be followed by a integer value which specified the node on which
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-to execute the codelet.
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-@end defmac
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-
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-@defmac STARPU_EXECUTE_ON_DATA
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-this macro is used when calling @code{starpu_mpi_insert_task}, and
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-must be followed by a data handle to specify that the node owning the
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-given data will execute the codelet.
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-@end defmac
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-
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-@deftypefun int starpu_mpi_insert_task (MPI_Comm @var{comm}, struct starpu_codelet *@var{codelet}, ...)
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-Create and submit a task corresponding to @var{codelet} with the following
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-arguments. The argument list must be zero-terminated.
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-
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-The arguments following the codelets are the same types as for the
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-function @code{starpu_insert_task} defined in @ref{Insert Task
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-Utility}. The extra argument @code{STARPU_EXECUTE_ON_NODE} followed by an
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-integer allows to specify the MPI node to execute the codelet. It is also
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-possible to specify that the node owning a specific data will execute
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-the codelet, by using @code{STARPU_EXECUTE_ON_DATA} followed by a data
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-handle.
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-
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-The internal algorithm is as follows:
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-@enumerate
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-@item Find out which MPI node is going to execute the codelet.
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- @enumerate
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- @item If there is only one node owning data in W mode, it will
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- be selected;
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- @item If there is several nodes owning data in W node, the one
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- selected will be the one having the least data in R mode so as
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- to minimize the amount of data to be transfered;
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- @item The argument @code{STARPU_EXECUTE_ON_NODE} followed by an
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- integer can be used to specify the node;
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- @item The argument @code{STARPU_EXECUTE_ON_DATA} followed by a
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- data handle can be used to specify that the node owing the given
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- data will execute the codelet.
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- @end enumerate
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-@item Send and receive data as requested. Nodes owning data which need to be
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-read by the task are sending them to the MPI node which will execute it. The
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-latter receives them.
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-@item Execute the codelet. This is done by the MPI node selected in the
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-1st step of the algorithm.
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-@item If several MPI nodes own data to be written to, send written
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-data back to their owners.
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-@end enumerate
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-
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-The algorithm also includes a communication cache mechanism that
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-allows not to send data twice to the same MPI node, unless the data
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-has been modified. The cache can be disabled
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-(@pxref{STARPU_MPI_CACHE}).
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-@c todo parler plus du cache
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-
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-@end deftypefun
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-
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-@deftypefun void starpu_mpi_get_data_on_node (MPI_Comm @var{comm}, starpu_data_handle_t @var{data_handle}, int @var{node})
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-Transfer data @var{data_handle} to MPI node @var{node}, sending it from its
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-owner if needed. At least the target node and the owner have to call the
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-function.
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-@end deftypefun
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+The list of functions are described in @ref{MPI Insert Task}.
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Here an stencil example showing how to use @code{starpu_mpi_insert_task}. One
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first needs to define a distribution function which specifies the
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locality of the data. Note that that distribution information needs to
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-be given to StarPU by calling @code{starpu_data_set_rank}.
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+be given to StarPU by calling @code{starpu_data_set_rank}. A MPI tag
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+should also be defined for each data handle by calling
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+@code{starpu_data_set_tag}.
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@cartouche
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@smallexample
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@@ -371,8 +294,10 @@ data which will be needed by the tasks that we will execute.
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else
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/* I know it's useless to allocate anything for this */
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data_handles[x][y] = NULL;
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- if (data_handles[x][y])
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+ if (data_handles[x][y]) @{
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starpu_data_set_rank(data_handles[x][y], mpi_rank);
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+ starpu_data_set_tag(data_handles[x][y], x*X+y);
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+ @}
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@}
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@}
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@end smallexample
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Nathalie Furmento