[CMake] Tips on reducing configure time

[Eric Noulard]

Le mer. 14 nov. 2018 à 12:06, Poughon Victor <Victor.Poughon at cnes.fr> a
écrit :

> Thanks for the replies
>
>
>
> You can see configure times on our dashboard (switch to advanced view):
> https://dash.orfeo-toolbox.org/index.php?project=OTB
>
> It ranges from 1-3min. There's even one windows machine that's at 4m30s.
>

Somes windows system are known to be slow on many files accesses.
However on this particular machine (
https://dash.orfeo-toolbox.org/buildSummary.php?buildid=342008 I guess) you
already seem
to be using NInja + MSVC. so many small files access to ?makefiles? should
not be the culprit.

That said whatever the system your build and test time seems to dominate
the overall time (in the CI).

I have had great speed-up experience using CMake+ninja+ccache  for our
build in CI. We did go from 1 hour down to less than 10min.
We only have various linux build (no Windows) it is really a big time
savior combo.

We even share the compil' cache between the CI and the developers. So
everybody is feeding compile cache and takes benefits from others including
CI.

You seem to be using that as well here:
https://dash.orfeo-toolbox.org/buildSummary.php?buildid=341993
and you get less than 5min build time which corroborate my suggestion.

The same machine build with clang:
https://dash.orfeo-toolbox.org/buildSummary.php?buildid=342033 is lasting
30min+
and is not using ccache.


> Thanks for the tip about Ninja generator, it's indeed much faster. But
> switching the entire dev team + CI servers from make to ninja is not really
> an option for us right now because of a bug in ninja that affects our
> SuperBuild configuration (see here if you're interested in the details:
> https://gitlab.orfeo-toolbox.org/orfeotoolbox/otb/issues/1625)
>

I see.
Not using ninja in the Superbuild case does not mean you cannot use it in
other cases, right?
May be the one-size fits all is a little too much to ask at this point? My
opinion though.
Did you report the issue upstream (ninja or cmake)?

I was impressed in the past by the amount of tests orfeo is doing, I'm
still are !!
Are you running those tests in parallel (with ctest --parallel) ? It can be
a time savior as well is the running machine has a fair amount of cores and
memory.


-- 
Eric
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://cmake.org/pipermail/cmake/attachments/20181114/05178cf3/attachment.html>