[petsc-users] Bad memory scaling with PETSc 3.10

[Mark Adams]

On Mon, Mar 11, 2019 at 6:32 AM Myriam Peyrounette <
myriam.peyrounette at idris.fr> wrote:

> Hi,
>
> good point, I changed the 3.10 version so that it is configured with
> --with-debugging=0. You'll find attached the output of the new LogView. The
> execution time is reduced (although still not as good as 3.6) but I can't
> see any improvement with regard to memory.
>
> You'll also find attached the grep GAMG on -info outputs for both
> versions. There are slight differences in grid dimensions or nnz values,
> but is it significant?
>

No. And the GAMG runs seem to be on a 13x13x13 grid.

The nnz goes down a lot here, which is odd, but the problem is so small
that we are probably just seeing boundary effects.


> Thanks,
>
> Myriam
>
>
>
> Le 03/08/19 à 23:23, Mark Adams a écrit :
>
> Just seeing this now. It is hard to imagine how bad GAMG could be on a
> coarse grid, but you can run with -info and grep on GAMG and send that. You
> will see listing of levels, number of equations and number of non-zeros
> (nnz). You can send that and I can get some sense of GAMG is going nuts.
>
> Mark
>
> On Fri, Mar 8, 2019 at 11:56 AM Jed Brown via petsc-users <
> petsc-users at mcs.anl.gov> wrote:
>
>> It may not address the memory issue, but can you build 3.10 with the
>> same options you used for 3.6?  It is currently a debugging build:
>>
>>               ##########################################################
>>               #                                                        #
>>               #                       WARNING!!!                       #
>>               #                                                        #
>>               #   This code was compiled with a debugging option.      #
>>               #   To get timing results run ./configure                #
>>               #   using --with-debugging=no, the performance will      #
>>               #   be generally two or three times faster.              #
>>               #                                                        #
>>               ##########################################################
>>
>>
> --
> Myriam Peyrounette
> CNRS/IDRIS - HLST
> --
>
>
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