[petsc-users] Question about time issues in parallel computing

[Matthew Knepley]

On Wed, Mar 15, 2023 at 3:38 AM ­권승리 / 학생 / 항공우주공학과 <ksl7912 at snu.ac.kr>
wrote:

> Dear petsc developers.
>
> Hello.
> I am trying to solve the structural problem with FEM and test parallel
> computing works well.
>
> However, even if I change the number of cores, the total time is
> calculated the same.
>
> I have tested on a simple problem using a MUMPS solver using:
> mpiexec -n 1
> mpiexec -n 2
> mpiexec -n 4
> ...
>
> Could you give me some advice if you have experienced this problem?
>

If your problem is small, you could very well see no speedup:


https://petsc.org/main/faq/#what-kind-of-parallel-computers-or-clusters-are-needed-to-use-petsc-or-why-do-i-get-little-speedup

  Thanks,

     Matt


> Best regards
> Seung Lee Kwon
> --
> Seung Lee Kwon, Ph.D.Candidate
> Aerospace Structures and Materials Laboratory
> Department of Mechanical and Aerospace Engineering
> Seoul National University
> Building 300 Rm 503, Gwanak-ro 1, Gwanak-gu, Seoul, South Korea, 08826
> E-mail : ksl7912 at snu.ac.kr
> Office : +82-2-880-7389
> C. P : +82-10-4695-1062
>


-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener

https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>
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