On 05/07/2014 03:10 PM, Richard Shaw wrote:
Thanks Rob. I'll keep track of it over there. How often do updated versions of ROMIO get pulled over from MPICH into OpenMPI? On a slightly related note, I think I heard that you had fixed the 32bit issues in ROMIO that were causing it to break when reading more than 2 GB (i.e. http://www.open-mpi.org/community/lists/users/2012/07/19762.php). Have those been pulled into OpenMPI? I've been staying clear of ROMIO for a while (in favour of OMPIO), to avoid those issues.
Looks like I fixed that late last year. A slew of ">31 bit transfers" fixes went into the MPICH-3.1 release. Slurping those changes, which are individually small (using some _x versions of type-inquiry routines here, some MPI_Count promotions there) but pervasive, might give OpenMPI a bit of a headache.
==rob
Thanks, Richard On 7 May 2014 12:36, Rob Latham <r...@mcs.anl.gov <mailto:r...@mcs.anl.gov>> wrote: On 05/05/2014 09:20 PM, Richard Shaw wrote: Hello, I think I've come across a bug when using ROMIO to read in a 2D distributed array. I've attached a test case to this email. Thanks for the bug report and the test case. I've opened MPICH bug (because this is ROMIO's fault, not OpenMPI's fault... until I can prove otherwise ! :>) http://trac.mpich.org/__projects/mpich/ticket/2089 <http://trac.mpich.org/projects/mpich/ticket/2089> ==rob In the testcase I first initialise an array of 25 doubles (which will be a 5x5 grid), then I create a datatype representing a 5x5 matrix distributed in 3x3 blocks over a 2x2 process grid. As a reference I use MPI_Pack to pull out the block cyclic array elements local to each process (which I think is correct). Then I write the original array of 25 doubles to disk, and use MPI-IO to read it back in (performing the Open, Set_view, and Real_all), and compare to the reference. Running this with OMPI, the two match on all ranks. > mpirun -mca io ompio -np 4 ./darr_read.x === Rank 0 === (9 elements) Packed: 0.0 1.0 2.0 5.0 6.0 7.0 10.0 11.0 12.0 Read: 0.0 1.0 2.0 5.0 6.0 7.0 10.0 11.0 12.0 === Rank 1 === (6 elements) Packed: 15.0 16.0 17.0 20.0 21.0 22.0 Read: 15.0 16.0 17.0 20.0 21.0 22.0 === Rank 2 === (6 elements) Packed: 3.0 4.0 8.0 9.0 13.0 14.0 Read: 3.0 4.0 8.0 9.0 13.0 14.0 === Rank 3 === (4 elements) Packed: 18.0 19.0 23.0 24.0 Read: 18.0 19.0 23.0 24.0 However, using ROMIO the two differ on two of the ranks: > mpirun -mca io romio -np 4 ./darr_read.x === Rank 0 === (9 elements) Packed: 0.0 1.0 2.0 5.0 6.0 7.0 10.0 11.0 12.0 Read: 0.0 1.0 2.0 5.0 6.0 7.0 10.0 11.0 12.0 === Rank 1 === (6 elements) Packed: 15.0 16.0 17.0 20.0 21.0 22.0 Read: 0.0 1.0 2.0 0.0 1.0 2.0 === Rank 2 === (6 elements) Packed: 3.0 4.0 8.0 9.0 13.0 14.0 Read: 3.0 4.0 8.0 9.0 13.0 14.0 === Rank 3 === (4 elements) Packed: 18.0 19.0 23.0 24.0 Read: 0.0 1.0 0.0 1.0 My interpretation is that the behaviour with OMPIO is correct. Interestingly everything matches up using both ROMIO and OMPIO if I set the block shape to 2x2. This was run on OS X using 1.8.2a1r31632. I have also run this on Linux with OpenMPI 1.7.4, and OMPIO is still correct, but using ROMIO I just get segfaults. Thanks, Richard _________________________________________________ users mailing list us...@open-mpi.org <mailto:us...@open-mpi.org> http://www.open-mpi.org/__mailman/listinfo.cgi/users <http://www.open-mpi.org/mailman/listinfo.cgi/users> -- Rob Latham Mathematics and Computer Science Division Argonne National Lab, IL USA _________________________________________________ users mailing list us...@open-mpi.org <mailto:us...@open-mpi.org> http://www.open-mpi.org/__mailman/listinfo.cgi/users <http://www.open-mpi.org/mailman/listinfo.cgi/users> _______________________________________________ users mailing list us...@open-mpi.org http://www.open-mpi.org/mailman/listinfo.cgi/users
-- Rob Latham Mathematics and Computer Science Division Argonne National Lab, IL USA
