[petsc-dev] GAMG and custom MatMults in smoothers

[Stefano Zampini]

The intent was not to show you a deadlock; was to provide you evidence that
the PetscLogEvent model is meant to have the same event created
collectively (hopefully at class registration) on all processes. See also
PetscLogViewDefault

2018-07-02 18:45 GMT+03:00 Vaclav Hapla <vaclav.hapla at erdw.ethz.ch>:

> Thanks for the MWE. But it behaves exactly as I would anticipate, see log.
> I think that naming the event differently for each rank is not good but
> fortunately PETSc just ignores this for rank > 0. Important is the event id
> which is the same. I correctly get that the time spent in this event is
> slightly more than 8 s and the ratio between the shortest and the longest
> time among all ranks is 8.0.
>
> Where's the deadlock? Note that PetscLogEventBegin/End and
> PetscStageLogPush/Pop are not collective!
>
> And thanks for another argument for better specificity of the log view. If
> the same event would be nested at several levels, the obtained total time
> wouldn't say anything useful.
>
> Thanks
>
> Vaclav
>
>
>
> 2. 7. 2018 v 17:20, Stefano Zampini <stefano.zampini at gmail.com>:
>
>
>
>
>> I don't see why this should lead to deadlock? With current class-wise
>> events you can already have many simultaneous instances of the same event
>> at once.
>>
>>
> Attached a MVE to better explain myself. If you run with p processes, you
> will see what I mean
>
>
>
> --
> Stefano
> <log.c>
>
>
>
>


-- 
Stefano
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