Thanks Quincey, this is good to know. Mark On Thu, Jul 8, 2010 at 9:43 AM, Quincey Koziol <[email protected]> wrote: > Hi Mark, > > On Jul 8, 2010, at 11:07 AM, Mark Howison wrote: > >> Hi all, >> >> I'm wondering what happens internally in parallel HDF5 when two or >> more procs have overlapping hyperslab selections, e.g. when each proc >> has a layer of ghost zones for a stencil calculation and it tries to >> write all of the data including the ghost zones. >> >> Does HDF5 issue redundant read/write requests for the elements in the >> overlapping region? Or does it try to shrink the regions until they >> are disjoint? In the MPI-IO VFD, will the behavior depend on >> collective vs. independent mode? > > The HDF5 library doesn't check for overlapping selections and the > behavior is dependent on the timing of the I/O operations (for serial and > parallel independent I/O) and whatever the MPI library does (for parallel > collective I/O), but the MPI standard says that this operation's outcome is > undefined (and thus will likely be subject to timing or process ordering > issues). > > Quincey > > > _______________________________________________ > Hdf-forum is for HDF software users discussion. > [email protected] > http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org >
_______________________________________________ Hdf-forum is for HDF software users discussion. [email protected] http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org
