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

[Projet_TRIOU]

On 01/14/14 16:41, Karl Rupp wrote:
> Hi Pierre,
>
> > I try running in parallel the ex19 test case on CPU and GPU:
>>
>> OPT="_opt"
>> dir=/ccc/cont002/home/den/triou/Version_test_airain-hybrid/Trio_U/lib/src/LIBPETSC/petsc/linux$OPT/src/snes/examples/tutorials 
>>
>>
>> option="-pc_type none -ksp_type fgmres -snes_monitor_short -snes_rtol
>> 1.e-5 -log_summary -ksp_view -cuda_show_devices"
>> mpirun -np 2 $dir/ex19 $option 1>cpu$OPT.log 2>&1
>> mpirun -np 2 $dir/ex19 -dm_vec_type cusp -dm_mat_type aijcusp $option
>> 1>gpu$OPT.log 2>&1
>>
>> With OPT="", PETSc optimized library is used, parallel calculation runs
>> well on CPU and GPU.
>> With OPT="_opt", PETSc non optimized library is used, parallel
>> calculation crashes on GPU (it is OK on CPU).
>>
>> I join the log files. The only difference seems that PETSc-dev is built
>> with -O3 intead of -g...
>> I could try to rebuild PETSc with -O2 but do you have any idea of the
>> problem ?
>
> 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)

I could add that the "mpirun -np 1 ex19" runs well for all builds on CPU 
and GPU.

Pierre
>
> Best regards,
> Karli
>
>


-- 
*Trio_U support team*
Marthe ROUX (Saclay)
Pierre LEDAC (Grenoble)
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