[petsc-dev] Memory problem with OpenMP and Fieldsplit sub solvers

[Barry Smith]

  Can valgrind run and help with OpenMP?

  You can run in the debugger and find any calls to the options checking inside your code block and comment them all out to see if that eliminates the problem.

  Also generically how safe is CUDA inside OpenMP? That is with multiple threads calling CUDA stuff?


  Barry



> On Jan 18, 2021, at 7:04 PM, Mark Adams <mfadams at lbl.gov> wrote:
> 
> 
> Added this w/o luck:
> 
> #if defined(PETSC_HAVE_CUDA)
>   ierr = PetscOptionsCheckCUDA(logView);CHKERRQ(ierr);
> #if defined(PETSC_HAVE_THREADSAFETY)
>   ierr = PetscCUPMInitializeCheck();CHKERRQ(ierr);
> #endif
> #endif
>  
> Do you think I should keep this in or take it out? Seems like a good idea and when it all works we can see if we can make it lazy.
> 
> 1)  Calling PetscOptions inside threads. I looked quickly at the code and it seems like it should be ok but perhaps not. This is one reason why having stuff like PetscOptionsBegin inside a low-level creation VecCreate_SeqCUDA_Private is normally not done in PETSc. Eventually this needs to be moved or reworked. 
> 
> 
> I will try this next. It is hard to see the stack here. I think I will put it in ddt and put a breakpoint PetscOptionsEnd_Private. Other ideas welcome.
> 
> Mark
>  
> 2) PetscCUDAInitializeCheck is not thread safe.If it is being call for the first timeby multiple threads there can be trouble. So edit init.c and under
> 
> #if defined(PETSC_HAVE_CUDA)
>   ierr = PetscOptionsCheckCUDA(logView);CHKERRQ(ierr);
> #endif
> 
> #if defined(PETSC_HAVE_HIP)
>   ierr = PetscOptionsCheckHIP(logView);CHKERRQ(ierr);
> #endif
> 
> put in 
> #if defined thread safety
> PetscCUPMInitializeCheck
> #endif
> 
> this will force the initialize to be done before any threads are used 
> 

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