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Stores MPI IO communicator information to a file access property list (REMOVED)

FUNCTION REMOVED: The C functions H5P_SET_FAPL_MPIPOSIX and H5P_GET_FAPL_MPIPOSIX and the corresponding Fortran subroutines have been removed from the HDF5 library at Release 1.8.13. They remain available in earlier releases, through HDF5 Release 1.8.12.

All applications used with HDF5 Release 1.8.13 or later and that use MPI I/O should use the functions H5P_SET_FAPL_MPIO and H5P_GET_FAPL_MPIO or the corresponding Fortran subroutines.

While HDF5’s MPI-POSIX driver (H5P_SET_FAPL_MPIPOSIX and H5P_GET_FAPL_MPIPOSIX) once provided performance benefits on some systems, that is no longer the case. HDF5’s MPIO driver (H5P_SET_FAPL_MPIO and H5P_GET_FAPL_MPIO) now provides as good or better performance on all modern systems.


H5P_SET_FAPL_MPIPOSIX ( fapl_id, comm, use_gpfs_hints )



herr_t H5Pset_fapl_mpiposix(
                     hid_t fapl_id,
                     MPI_Comm comm,
                     hbool_t use_gpfs_hints

Fortran90 Interface: h5pset_fapl_mpiposix_f
SUBROUTINE h5pset_fapl_mpiposix_f(prp_id, comm, use_gpfs, hdferr)
  INTEGER(HID_T), INTENT(IN) :: prp_id  ! Property list identifier
  INTEGER, INTENT(IN) :: comm           ! MPI communicator to be used 
                                        ! for file open as defined in 
                                        ! MPI_FILE_OPEN of MPI-2
  LOGICAL, INTENT(IN) :: use_gpfs
  INTEGER, INTENT(OUT) :: hdferr        ! Error code
END SUBROUTINE h5pset_fapl_mpiposix_f

hid_t fapl_idIN: File access property list identifier
MPI_Comm commIN: MPI-2 communicator
hbool_t use_gpfs_hints    IN: Use of GPFS hints


H5P_SET_FAPL_MPIPOSIX stores the user-supplied MPI IO parameter comm, for communicator, in the file access property list fapl_id. That property list can then be used to create and/or open the file.

H5P_SET_FAPL_MPIPOSIX is available only in the parallel HDF5 library and is not a collective function.

comm is the MPI communicator to be used for file open, as defined in MPI_FILE_OPEN of MPI-2. This function does not create a duplicated communicator. Modifications to comm after this function call returns may have an undetermined effect on the file access property list. Users should not modify the communicator while it is defined in a property list.

use_gpfs_hints specifies whether to attempt to use GPFS hints when accessing this file. A value of 1 indicates that the hints should be used, if possible. A value of 0 indicates that the hints should not be used.

Available GPFS hints are known to the HFD5 library and are not user configurable. They may be used only with GPFS file systems and may improve file access for some applications; the user of a GPFS system is encouraged to experiment by running an application with and without this parameter set.

Raw dataset chunk caching is not currently supported when using this file driver in read/write mode. All calls to H5D_READ and H5D_WRITE will access the disk directly, and H5P_SET_CACHE and H5P_SET_CHUNK_CACHE will have no effect on performance.

Raw dataset chunk caching is supported when this driver is used in read-only mode.



Returns a non-negative value if successful. Otherwise returns a negative value.


Release    Change
1.8.13C function and Fortran subroutine removed from HDF5 at this release.
1.6.1Fortran subroutine introduced in this release.
1.6.0use_gpfs_hints parameter added.
1.6.0C function introduced in this release.

--- Last Modified: July 22, 2020 | 11:42 AM