MPI_Win_create(3) MPI MPI_Win_create(3)
NAME
MPI_Win_create - Create an MPI Window object for one-sided
communication
SYNOPSIS
int MPI_Win_create(void *base, MPI_Aint size, int disp_unit, MPI_Info info,
MPI_Comm comm, MPI_Win *win)
int MPI_Win_create_c(void *base, MPI_Aint size, MPI_Aint disp_unit,
MPI_Info info, MPI_Comm comm, MPI_Win *win)
INPUT PARAMETERS
base - initial address of window (choice)
size - size of window in bytes (non-negative integer)
disp_unit
- local unit size for displacements, in bytes (positive integer)
info - info argument (handle)
comm - intra-communicator (handle)
OUTPUT PARAMETERS
win - window object (handle)
NOTES
The displacement unit argument is provided to facilitate address
arithmetic in RMA operations: the target displacement argument of an
RMA operation is scaled by the factor disp_unit specified by the target
process, at window creation.
The info argument provides optimization hints to the runtime about the
expected usage pattern of the window. The following info keys are
predefined.
no_locks
- If set to true, then the implementation may assume that
passive target synchronization (i.e., MPI_Win_lock ,
MPI_Win_lock_all ) will not be used on the given window. This
implies that this window is not used for 3-party communication,
and RMA can be implemented with no (less) asynchronous agent
activity at this process.
accumulate_ordering
- Controls the ordering of accumulate operations at the target.
The argument string should contain a comma-separated list of the
following read/write ordering rules, where e.g. "raw" means
read-after-write: "rar,raw,war,waw".
accumulate_ops
- If set to same_op, the implementation will assume that all
concurrent accumulate calls to the same target address will use
the same operation. If set to same_op_no_op, then the
implementation will assume that all concurrent accumulate calls
to the same target address will use the same operation or
MPI_NO_OP . This can eliminate the need to protect access for
certain operation types where the hardware can guarantee
atomicity. The default is same_op_no_op.
mpi_accumulate_granularity
- Controls the desired synchronization granularity for
accumulate ops. It sets the size of memory range in bytes for
which the MPI library should acquire a synchronization primitive
to ensure the atomicity of updates. The default is 0 which let
the MPI library decides the granularity. When the info hint is
set to a positive value, the actual range of synchroniation is
round-up to the next size that fits the Datatype used in the
accumulate operation (see MPI standard 4.1). All processes in
the group of a windows must set to the same value.
THREAD AND INTERRUPT SAFETY
This routine is thread-safe. This means that this routine may be
safely used by multiple threads without the need for any user-provided
thread locks. However, the routine is not interrupt safe. Typically,
this is due to the use of memory allocation routines such as malloc or
other non-MPICH runtime routines that are themselves not interrupt-
safe.
NOTES FOR FORTRAN
All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have
an additional argument ierr at the end of the argument list. ierr is
an integer and has the same meaning as the return value of the routine
in C. In Fortran, MPI routines are subroutines, and are invoked with
the call statement.
All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in
Fortran.
ERRORS
All MPI routines (except MPI_Wtime and MPI_Wtick ) return an error
value; C routines as the value of the function and Fortran routines in
the last argument. Before the value is returned, the current MPI error
handler is called. By default, this error handler aborts the MPI job.
The error handler may be changed with MPI_Comm_set_errhandler (for
communicators), MPI_File_set_errhandler (for files), and
MPI_Win_set_errhandler (for RMA windows). The MPI-1 routine
MPI_Errhandler_set may be used but its use is deprecated. The
predefined error handler MPI_ERRORS_RETURN may be used to cause error
values to be returned. Note that MPI does not guarantee that an MPI
program can continue past an error; however, MPI implementations will
attempt to continue whenever possible.
MPI_SUCCESS
- No error; MPI routine completed successfully.
MPI_ERR_ARG
- Invalid argument. Some argument is invalid and is not
identified by a specific error class (e.g., MPI_ERR_RANK ).
MPI_ERR_COMM
- Invalid communicator. A common error is to use a null
communicator in a call (not even allowed in MPI_Comm_rank ).
MPI_ERR_DISP
-
MPI_ERR_INFO
- Invalid Info
MPI_ERR_SIZE
-
MPI_ERR_OTHER
- Other error; use MPI_Error_string to get more information
about this error code.
SEE ALSO
MPI_Win_allocate(3), MPI_Win_allocate_sharede(3),
MPI_Win_create_dynamice(3), MPI_Win_freee(3)
7/3/2024 MPI_Win_create(3)
mpi 4.2.2 - Generated Sat Aug 17 19:25:49 CDT 2024