[petsc-dev] [GPU] Crash on ex19 with mpirun -np 2 (optimized build)

[Paul Mullowney]

Previously, I had noticed strange behaviour when running the GPU code with
the threadComm package. It might be worth trying to disable that code in
the build to see if the problem persists?
-Paul


On Tue, Jan 14, 2014 at 9:19 AM, Karl Rupp <rupp at mcs.anl.gov> wrote:

> Hi Pierre,
>
>
> >> I could reproduce the problem and also get some uninitialized variable
>
>> warnings in Valgrind. The debug version detects these errors, hence
>>> you only see the errors in the debug build. For the optimized build,
>>> chances are good that the computed values are either wrong or may
>>> become wrong in other environments. I'll see what I can do when I'm
>>> again at GPU machine tomorrow (parallel GPU debugging via SSH is not
>>> great...)
>>>
>> Sorry, I mean:
>>
>> Parallel calculation on CPU or GPU run well with PETSc non optimized
>> library
>> Parallel calculation on GPU crashes with PETSc optimized library (on CPU
>> it is OK)
>>
>
> The fact that it happens to run in one mode out of {debug, optimized} but
> not in the other is at most a lucky coincidence, but it still means that
> this is a bug we need to solve :-)
>
>
>
>  I could add that the "mpirun -np 1 ex19" runs well for all builds on CPU
>> and GPU.
>>
>
> I see valgrind warnings in the vector scatter routines, which is likely
> the reason why it doesn't work with multiple MPI ranks.
>
> Best regards,
> Karli
>
>
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