[petsc-users] Code speedup after upgrading

[Mohammad Gohardoust]

Thanks Dave for your reply.

For sure PETSc is awesome :D

Yes, in both cases petsc was configured with --with-debugging=0 and
fortunately I do have the old and new -log-veiw outputs which I attached.

Best,
Mohammad

On Tue, Mar 23, 2021 at 1:37 AM Dave May <dave.mayhem23 at gmail.com> wrote:

> Nice to hear!
> The answer is simple, PETSc is awesome :)
>
> Jokes aside, assuming both petsc builds were configured with
> —with-debugging=0, I don’t think there is a definitive answer to your
> question with the information you provided.
>
> It could be as simple as one specific implementation you use was improved
> between petsc releases. Not being an Ubuntu expert, the change might be
> associated with using a different compiler, and or a more efficient BLAS
> implementation (non threaded vs threaded). However I doubt this is the
> origin of your 2x performance increase.
>
> If you really want to understand where the performance improvement
> originated from, you’d need to send to the email list the result of
> -log_view from both the old and new versions, running the exact same
> problem.
>
> From that info, we can see what implementations in PETSc are being used
> and where the time reduction is occurring. Knowing that, it should be
> clearer to provide an explanation for it.
>
>
> Thanks,
> Dave
>
>
> On Tue 23. Mar 2021 at 06:24, Mohammad Gohardoust <gohardoust at gmail.com>
> wrote:
>
>> Hi,
>>
>> I am using a code which is based on petsc (and also parmetis). Recently I
>> made the following changes and now the code is running about two times
>> faster than before:
>>
>>    - Upgraded Ubuntu 18.04 to 20.04
>>    - Upgraded petsc 3.13.4 to 3.14.5
>>    - This time I installed parmetis and metis directly via petsc by
>>    --download-parmetis --download-metis flags instead of installing them
>>    separately and using --with-parmetis-include=... and
>>    --with-parmetis-lib=... (the version of installed parmetis was 4.0.3 before)
>>
>> I was wondering what can possibly explain this speedup? Does anyone have
>> any suggestions?
>>
>> Thanks,
>> Mohammad
>>
>
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