[petsc-users] Hybrid MPI/OpenMP PETSc

[W. Miah]

Hi Barry,

Thanks for the reply. I'm looking to hybridise the TeaLeaf mini app,
and the Imperial College bunch have shown some performance
improvements for some CFD codes, but nothing really significant. I
haven't come across a code that improves massively with hybridisation.

TeaLeaf is just a small test - nothing significant. We'll see if it
improves anything. Of course, I won't call MatSetValues within an
OpenMP region :-) I asked because this is usually called within a loop
for populating the rows of the matrix.

Best regards,
Wadud.

On 1 July 2015 at 21:24, Barry Smith <bsmith at mcs.anl.gov> wrote:
>
>> On Jul 1, 2015, at 2:26 PM, W. Miah <wadud.miah at gmail.com> wrote:
>>
>> Hello,
>>
>> What is the status of hybrid PETSc (MPI/OpenMP)? Imperial College
>> developed a hybrid port and was wondering whether this has been merged
>> with the PETSc trunk.
>
>    At the moment we don't have any support for mixed MPI/OpenMP.
>
>    What do you need it for? Have you known cases where the performance would be much higher with mixed MPI/OpenMP? We've never seen fully open source software where mixed MPI/OpenMP performs much better (or even any better) than pure MPI.
>
>
>> Also, is the
>> MatSetValues subroutine thread safe, namely could it be called within
>> an OpenMP thread region (not simd)?
>
>    This will very likely never work.
>
>   Barry
>
>>
>> Best regards,
>> Wadud.
>



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