On Tue, Jun 29, 2010 at 19:35, Yujie <recrusader at gmail.com> wrote:
> Dear PETSc developers, > > I want to output an about 36K*36K dense matrix using MatView in binary > format. I use RedHat Enterprise 5 64bits system. However, when the > file size of output matrix reaches about 2.7G, the codes pause and > don't response for a long time (almost 3 hours). Could you help me > figure out what happened? Thanks a lot. > Were you writing this in serial or parallel? MPICH2 and Open MPI don't properly handle large message sizes fixes require ABI-incompatible changes that they don't want to push out in a minor release. I believe the latest versions of both will actually do the send, but MPI_Get_count does not return the correct value, and it probably would not be surprising if some MPI-IO functionality did not work correctly with large messages. Tickets that I'm familiar with: https://trac.mcs.anl.gov/projects/mpich2/ticket/1005 https://svn.open-mpi.org/trac/ompi/ticket/2241 I think they should both be fine for MPI-IO as long as each processor sends less than 2 GiB (even though the final output may be much bigger). If this happens again, you could attach a debugger to the running process (gdb -pid XXX) and get a backtrace. Note that you can build "optimized" with debugging symbols at a very small runtime penalty. Jed -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20100629/1c5338cc/attachment-0001.htm>
