Hi,
I am trying to debug a large iterative solver that has been compiled using
intel fortran 10 and open mpi 1.2.6. that is run in a SLES10 based PC cluster
using valgrind 3.5.0. To supress the openmpi error messages I've put mpi
argument "--mca btl tcp, self", otherwise the log file is simply filled by open
mpi messages, which may amount to 20Mb. Here, I am not trying to debug the open
mpi.
The problem appears at random in after several iterations which suggest a
memory related problem. I expect Memcheck to report an error when the offending
lines is executed for the first time. However, Memcheck does not report up any
problem prior to the point of failure, i.e. the part of the code that fail has
been passed by Memcheck as problem free in previous iterations. At the point of
failure, typically the following error is logged by memcheck
Invalid write of size 8
at 0x511BF6B: _int_malloc (in
/opt/openmpi-1.2.6/intel/lib/libopen-pal.so.0.0.0)
by 0x511B710: malloc (in /opt/openmpi-1.2.6/intel/lib/libopen-pal.so.0.0.0)
by 0x907161A: ompi_coll_tuned_allreduce_intra_recursivedoubling (in
/opt/openmpi-1.2.6/intel/lib/mca_coll_tuned.so)
by 0x906FFED: ompi_coll_tuned_allreduce_intra_dec_fixed (in
/opt/openmpi-1.2.6/intel/lib/mca_coll_tuned.so)
by 0x4DFFEF7: PMPI_Allreduce (in /opt/openmpi-1.2.6/intel/lib/libmpi.so.0.0.0)
by 0x4C9C612: PMPI_ALLREDUCE (in
/opt/openmpi-1.2.6/intel/lib/libmpi_f77.so.0.0.0)
by 0x6E006E: my_mpireduce_call (my_routine.F)
.
.
.
Adress 0x10 is not stack'd, malloc'd or (recently) free'd
Since memcheck does not detect any problem earlier when the point of failure is
executed, does it mean the program is fairly sound? I could not see any bug at
the program line that call the mpi reduce.
Does that error message suggest the dynamic memory allocation within open-mpi
allreduce operation is at fault? If this is the case, could I capture the
problem earlier by removing the mpi suppression ?
Regards
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