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

[Projet_TRIOU]

Hello Karl,

Thanks for fixing the problem. ex19 runs now in parallel on GPU
on the last petsc-dev versions.
I got another problem though but will create another thread.

PL
> 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
>


-- 
*Trio_U support team*
Marthe ROUX (01 69 08 00 02) Saclay
Pierre LEDAC (04 38 78 91 49) Grenoble
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