H5Pset_dxpl_mpio_collective_opt
(hid_t dxpl_id
,
H5FD_mpio_collective_opt_t opt_mode
)
H5Pset_dxpl_mpio_collective_opt
enables an application
to specify that the HDF5 Library will use independent I/O internally
when the dataset transfer property list dxpl_id
is set for collective I/O,
i.e., with H5FD_MPIO_COLLECTIVE
specified.
This allows the application greater control over low-level I/O
while maintaining the collective interface at the application level.
H5Pset_dxpl_mpio_collective_opt
works by setting one of the
following flags in the parameter opt_mode
:
H5FD_MPIO_COLLECTIVE_IO |
Use collective I/O. (Default) |
H5FD_MPIO_INDIVIDUAL_IO |
Use independent I/O. |
This function should be used only when H5FD_MPIO_COLLECTIVE
has been set through H5Pset_dxpl_mpio
.
In such situations, normal behavior would be to use
low-level collective I/O functions,
but the library will use low-level MPI independent I/O functions
when H5FD_MPIO_INDIVIDUAL_IO
is set.
Use of this function is optional.
hid_t dxpl_id |
IN: Data transfer property list identifier |
H5FD_mpio_collective_opt_t opt_mode |
IN: Optimization flag specifying the use of independent or collective I/O |