On Wed, Dec 8, 2010 at 5:38 PM, Leigh Orf <[email protected]> wrote: > My question is: can I do the round-robin write part without having to open > and close (h5fopen_f / h5fclose_f) the file for each core? It seems that > file_id (and the other id's like dset_id, dspace_id etc.) carries with it > something tangible that links that id to the file itself. I don't think I > can get away with doing MPI_BCAST of the file_id (and the other id > variables) to the other cores and use those handles to magically access the > file created on the root core... right? I am trying to avoid the overhead of > opening, seeking, closing for each core.
Quincey, is H5Fcreate/open already using an MPI_BCAST under the covers? If not, there is another optimization that I think was reported in a paper on PLFS or Adios about passing a flag to the fopen call on each MPI task that tells it not to update the creation/modification time except on the root task. This can greatly reduce the load on the metadata server for a parallel file system. Mark _______________________________________________ Hdf-forum is for HDF software users discussion. [email protected] http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org
