[petsc-users] Scaling problem when cores > 600

[Matthew Knepley]

On Wed, Feb 28, 2018 at 10:45 AM, TAY wee-beng <zonexo at gmail.com> wrote:

> Hi,
>
> I have a CFD code which uses PETSc and HYPRE. I found that for a certain
> case with grid size of 192,570,048, I encounter scaling problem when my
> cores > 600. At 600 cores, the code took 10min for 100 time steps. At 960,
> 1440 and 2880 cores, it still takes around 10min. At 360 cores, it took
> 15min.
>
> So how can I find the bottleneck? Any recommended steps?
>

For any performance question, we need to see the output of -log_view for
all test cases.


> I must also mention that I partition my grid only in the x and y
> direction. There is no partitioning in the z direction due to limited code
> development. I wonder if there is a strong effect in this case.


Maybe. Usually what happens is you fill up memory with a z-column and
cannot scale further.

  Thanks,

     Matt


>
> --
> Thank you very much
>
> Yours sincerely,
>
> ================================================
> TAY Wee-Beng 郑伟明 (Zheng Weiming)
> Personal research webpage: http://tayweebeng.wixsite.com/website
> Youtube research showcase: https://www.youtube.com/channe
> l/UC72ZHtvQNMpNs2uRTSToiLA
> linkedin: www.linkedin.com/in/tay-weebeng
> ================================================
>
>


-- 
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.caam.rice.edu/~mk51/>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20180228/be040644/attachment.html>