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

[Karl Rupp]

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