[mpich-discuss] MPI-IO of multidimensional arrays - issue reported by valgrind

[Rob Latham]

On Tue, Feb 23, 2010 at 11:54:24AM +0000, Turlough Downes wrote:
> To do this I'm using MPI_Type_create_subarray(), MPI_File_open(),
> MPI_File_set_view() and MPI_File_write_all().  My problem is that my
> code is occasionally hanging on output on a Blue Gene/P system.  

What file system are you using on this BlueGene system?  If you can
get your program to dump core, you can print a backtrace.  That
backtrace will help us understand if this is a true hang, or if
processes are just progressing very slowly.

> ==10315== Conditional jump or move depends on uninitialised value(s)
> ==10315==    at 0x4C86DE8: (within /usr/lib64/mpich2/lib/libmpich.so.1.2)
> ==10315==    by 0x4C88F0E: ADIOI_GEN_WriteStridedColl (in /usr/lib64/mpich2/lib/libmpich.so.1.2)
> ==10315==    by 0x4D678C6: MPIOI_File_write_all (in /usr/lib64/mpich2/lib/libmpich.so.1.2)
> ==10315==    by 0x4D679B8: PMPI_File_write_all (in /usr/lib64/mpich2/lib/libmpich.so.1.2)
> ==10315==    by 0x41B6B4: hydra_write_single_binary_file (out_binary_single_file.c:101)

We should probably be more careful with the 'conditional jump or move'
warnings, but they rarely if ever point to an actual defect. 

==rob

-- 
Rob Latham
Mathematics and Computer Science Division
Argonne National Lab, IL USA