[petsc-users] Hybrid MPI/OpenMP PETSc

W. Miah wadud.miah at gmail.com
Wed Jul 1 18:22:44 CDT 2015

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,

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.

email:   wadud.miah at gmail.com
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