yade-dev team mailing list archive

[Bruno Chareyre <bruno.chareyre@xxxxxxxxxxxxxxx>]

Hi Janek, thanks for pybind feedback. It is intriguing. It was definitely
after me mentionning compile times with boost for c++ / python, at a
workshop, that someone reached me and advised about pybind.
Rumor?

Bruno



Le dim. 23 févr. 2020 16:03, Janek Kozicki (yade) <jkozicki-yade@xxxxxxxxx>
a écrit :

> > Another note: I just realized that the compilation benchmarks might
> > have not been fair, because I think that I added few more
> > registrations (like Vector2c, or sth. like that) while doing pybind
> > migration. I will compare again without these extra registrations.
>
> OK, I have compared with the exact same registrations. And it seems
> that pybind has many advantages, but not the one that it is compiling
> faster. See:
>
> pybind without debug info; call `ccache --clear` between every invocation.
> -O3 -j 1                           -O3 -j 10
>     wall clock time: 2:41.14           wall clock time: 0:40.67
>     wall clock time: 2:46.56           wall clock time: 0:41.28
>     wall clock time: 2:47.42           wall clock time: 0:42.54
>     wall clock time: 2:43.79           wall clock time: 0:44.70
>
> -O1 -j 1                           -O1 -j 10
>     wall clock time: 2:09.88           wall clock time: 0:35.00
>     wall clock time: 2:10.78           wall clock time: 0:33.46
>     wall clock time: 2:08.19           wall clock time: 0:32.62
>     wall clock time: 2:10.10           wall clock time: 0:32.73
>
>
> ================================================================================
> boost::python without debug info; call `ccache --clear` between every
> invocation.
> -O3 -j 1                           -O3 -j 10
>     wall clock time: 2:16.83           wall clock time: 0:33.88
>     wall clock time: 2:15.96           wall clock time: 0:32.84
>     wall clock time: 2:16.00           wall clock time: 0:34.85
>     wall clock time: 2:16.52           wall clock time: 0:32.32
>
> -O1 -j 1                           -O1 -j 10
>     wall clock time: 2:01.48           wall clock time: 0:28.56
>     wall clock time: 2:00.70           wall clock time: 0:29.15
>     wall clock time: 2:01.29           wall clock time: 0:28.05
>     wall clock time: 2:00.56           wall clock time: 0:28.35
>
> The main pybind disadvantage is unstable API. I don't like writing
> extra code to support older linux distributions.
>
>
> Also I think that if while copying minieigen into yade we did some
> extra rebalancing between the .cpp files, so that in each file there's
> about the same amount of registrations performed, then we could
> reduce (parallel) compilation time to maybe 25 or 20 seconds.
>
>
> If you wanted to compile and try yourself, the comparison was between
> branches master and tryPybind. To see how to compile see .gitlab-ci.yml,
> I'm sorry that it's a bit messy. I was never good at using build
> systems ;) I just wanted parallel build quickly. That's why I wrote
> such strange makefile.
>
> best regards
> Janek
>
>
>
> > Another comparison note:
> >
> > 8. boost::python is much more picky about the order of registered
> >    functions, and sometimes does not work if the order is "wrong".
> >    pybind always resolves the function overloads correctly.
>
> --
> --
> Janek Kozicki, PhD. DSc. Arch. Assoc. Prof.
> Gdańsk University of Technology
> Faculty of Applied Physics and Mathematics
> Department of Theoretical Physics and Quantum Information
> --
> http://yade-dem.org/
> http://pg.edu.pl/jkozicki (click English flag on top right)
>
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