[CMake] Tips on reducing configure time

[Poughon Victor]

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.

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)


Victor Poughon

De : Eric Noulard <eric.noulard at gmail.com>
Envoyé : mercredi 14 novembre 2018 11:12
À : Poughon Victor <Victor.Poughon at cnes.fr>
Cc : CMake Mailinglist <cmake at cmake.org>
Objet : Re: [CMake] Tips on reducing configure time

Hi Victor,
Le mer. 14 nov. 2018 à 10:20, Poughon Victor <Victor.Poughon at cnes.fr<mailto:Victor.Poughon at cnes.fr>> a écrit :
Hi all

I am working on a large C++ project using CMake (https://www.orfeo-toolbox.org/) and our 'configure' step takes quite a lot of time. This can be annoying for developers working on features where the configure step needs to be re-run, or for CI in general.

Could you give us a clue on "takes quite a lot of time"?
Are we speaking of tens of seconds, minutes etc... ?


We have looked into it a bit and it seems like one issue is that the configure/generate steps do a lot of small files I/O. Specifically, using:

    inotofy-wait -mr <build_dir>

shows that "cmake ." causes about 150K file access/modify, etc. There are some especially guilty looking files like 'Makefile2.tmp' or 'progress.tmp' that appear thousands of times in most of the log file.

I have an SSD which somewhat helps, but for colleagues still on mechanical drives this is especially painful. Is there a way to disable writing all those files to the disk?

Any other tips on optimizing the performance of 'cmake .'?

Did you try to test drive a switch to ninja generator ?
Ninja generator generates only two files (build.ninja and rules.ninja) you won't have the "mny small files issue".
You can have long configuration times as well but not coming from file access.




Thanks,

Victor Poughon


--

Powered by www.kitware.com<http://www.kitware.com>

Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ

Kitware offers various services to support the CMake community. For more information on each offering, please visit:

CMake Support: http://cmake.org/cmake/help/support.html
CMake Consulting: http://cmake.org/cmake/help/consulting.html
CMake Training Courses: http://cmake.org/cmake/help/training.html

Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html

Follow this link to subscribe/unsubscribe:
https://cmake.org/mailman/listinfo/cmake


--
Eric
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://cmake.org/pipermail/cmake/attachments/20181114/08be471b/attachment.html>