[petsc-dev] odd log behavior
Mark Adams
mfadams at lbl.gov
Wed Apr 27 09:08:14 CDT 2022
On Tue, Apr 26, 2022 at 8:00 PM Barry Smith <bsmith at petsc.dev> wrote:
>
> The current nan output has to be replaced to get the column alignment
> correct, I just didn't feel like making that change also in the same MR.
>
> Something like Unknown or anything that fits in the column space would
> be fine. It just means for the given run the timing numbers are not
> meaningful/correct for those events.
>
Just a note, just about every event is NAN for me. My GAMG setup that is
all CPU is NAN. High level functions like PtAP as well.
That said, adding -log_view_gpu_time is fine. Not worth the churn.
> This is to obtain the best meaningful results for the outer events per Jed
> since timing the inner events accurately introduces extra time in the outer
> events. That is it is not possible to have the best accurate times for both
> inner events and outer events in the same run. So if you want to compare
> KSPSolve timings, for example, you run as-is, it you want to examine,
> low-level vector operations run also with -log_view_gpu_time but know that
> the KSP times are higher than need be.
>
> Sorry for the confusion.
>
>
>
>
> On Apr 26, 2022, at 3:49 PM, Matthew Knepley <knepley at gmail.com> wrote:
>
> On Tue, Apr 26, 2022 at 12:03 PM Mark Adams <mfadams at lbl.gov> wrote:
>
>> Well, Nans are a clear sign that something is very wrong.
>>
>
> Barry chose them so that it could not be mistaken for an actual number.
>
> Matt
>
>
>> On Tue, Apr 26, 2022 at 11:52 AM Jacob Faibussowitsch <
>> jacob.fai at gmail.com> wrote:
>>
>>> There is an automatic warning that shows when you do run with
>>> `-log_view_gpu_time`, but perhaps there should also be an automatic warning
>>> when *not* running with it. It is unfortunate that NaN is the value printed
>>> as this implies a bug but AFAIK it is unavoidable (Barry can say more on
>>> this though).
>>>
>>> Best regards,
>>>
>>> Jacob Faibussowitsch
>>> (Jacob Fai - booss - oh - vitch)
>>>
>>> > On Apr 26, 2022, at 09:48, Jose E. Roman <jroman at dsic.upv.es> wrote:
>>> >
>>> > You have to add -log_view_gpu_time
>>> > See https://gitlab.com/petsc/petsc/-/merge_requests/5056
>>> >
>>> > Jose
>>> >
>>> >
>>> >> El 26 abr 2022, a las 16:39, Mark Adams <mfadams at lbl.gov> escribió:
>>> >>
>>> >> I'm seeing this on Perlmutter with Kokkos-CUDA. Nans in most log
>>> timing data except the two 'Solve' lines.
>>> >> Just cg/jacobi on snes/ex56.
>>> >>
>>> >> Any ideas?
>>> >>
>>> >> VecTDot 2 1.0 nan nan 1.20e+01 1.0 0.0e+00 0.0e+00
>>> 0.0e+00 0 0 0 0 0 0 0 0 0 0 -nan -nan 0 0.00e+00 0
>>> 0.00e+00 100
>>> >> VecNorm 2 1.0 nan nan 1.00e+01 1.0 0.0e+00 0.0e+00
>>> 0.0e+00 0 0 0 0 0 0 0 0 0 0 -nan -nan 0 0.00e+00 0
>>> 0.00e+00 100
>>> >> VecCopy 2 1.0 nan nan 0.00e+00 0.0 0.0e+00 0.0e+00
>>> 0.0e+00 0 0 0 0 0 0 0 0 0 0 -nan -nan 0 0.00e+00 0
>>> 0.00e+00 0
>>> >> VecSet 5 1.0 nan nan 0.00e+00 0.0 0.0e+00 0.0e+00
>>> 0.0e+00 0 0 0 0 0 0 0 0 0 0 -nan -nan 0 0.00e+00 0
>>> 0.00e+00 0
>>> >> VecAXPY 4 1.0 nan nan 2.40e+01 1.0 0.0e+00 0.0e+00
>>> 0.0e+00 0 0 0 0 0 1 0 0 0 0 -nan -nan 0 0.00e+00 0
>>> 0.00e+00 100
>>> >> VecPointwiseMult 1 1.0 nan nan 3.00e+00 1.0 0.0e+00 0.0e+00
>>> 0.0e+00 0 0 0 0 0 0 0 0 0 0 -nan -nan 0 0.00e+00 0
>>> 0.00e+00 100
>>> >> KSPSetUp 1 1.0 nan nan 0.00e+00 0.0 0.0e+00 0.0e+00
>>> 0.0e+00 0 0 0 0 0 0 0 0 0 0 -nan -nan 0 0.00e+00 0
>>> 0.00e+00 0
>>> >> KSPSolve 1 1.0 4.0514e-04 1.0 5.50e+01 1.0 0.0e+00
>>> 0.0e+00 0.0e+00 1 0 0 0 0 2 0 0 0 0 0 -nan 0
>>> 0.00e+00 0 0.00e+00 100
>>> >> SNESSolve 1 1.0 2.2128e-02 1.0 5.55e+05 1.0 0.0e+00
>>> 0.0e+00 0.0e+00 72 56 0 0 0 100100 0 0 0 25 -nan 0
>>> 0.00e+00 0 0.00e+00 0
>>> >
>>>
>>>
>
> --
> 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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