H5P_SET_DXPL_MPIO_COLLECTIVE_OPT
Sets a flag governing the use of independent versus collective I/O
Procedure:
H5P_SET_DXPL_MPIO_COLLECTIVE_OPT ( dxpl_id, opt_mode )
Signature:
herr_t H5Pset_dxpl_mpio_collective_opt
(hid_t dxpl_id,
H5FD_mpio_collective_opt_t opt_mode)
Parameters:
id_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 |
Description:
H5P_SET_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.
H5P_SET_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 H5P_SET_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.
Returns:
Returns a non-negative value if successful. Otherwise returns a negative value.
Example:
if(dxfer_coll_type == DXFER_INDEPENDENT_IO) {
status = H5Pset_dxpl_mpio_collective_opt(xfer_plist, H5FD_MPIO_INDIVIDUAL_IO);
History:
--- Last Modified: August 09, 2019 | 02:12 PM
