[cmake-developers] kwsysProcess threadsafety

[Jean-Michaël Celerier]

> 3) Abandon the idea to parallelize AUTOMOC/UIC

please no ! moc is a huge bottleneck in my builds (to the point that using
verdigris <https://github.com/woboq/verdigris> instead ends up having
faster build time overall).

Best,
Jean-Michaël



-------
Jean-Michaël Celerier
http://www.jcelerier.name

On Fri, Jan 5, 2018 at 8:34 PM, Sebastian Holtermann <seblist at xwmw.org>
wrote:

> Hello!
>
> As you might have noticed I tried to parallelize AUTOMOC/UIC.
> https://gitlab.kitware.com/cmake/cmake/merge_requests/1632
> The issue that's blocking it now is that the kwsysProcess framework
> isn't thread safe. As a consequence it is not possible for threads to
> start processes concurrently using the kwsysProcess framework.
>
> There are three options I see
>
> 1) Make kwsysProcess thread safe
>
> I don't think it's impossible but it's not a small task.
> Looking through the code I found a few issues that
> would block the whole idea for me.
>   - OpenVMS: I have little to no knowledge about OpenVMS.
>     Wikipedia says it is basically abandoned.
>     Can the OpenVMS code be removed? I couldn't test it anyway.
>
>   - C vs. C++
>     There's a lot of C in processUNIX.c (list allocation etc.).
>     I would prefer to use C++11 (or higher), especially
>     std::array, std::vector, std::thread,  std::mutex, etc..
>     Is C++11 acceptable in kwsysProcess?
>     This would make processUNIX.c processUNIX.cpp?
>
> 2) Use libuv instead
>
> Using the libuv event loop is overkill and would probably imply that
> more threads are started than necessary
> (the libuv thread pool will be started anyway).
> But it would allow to start multiple concurrent  (moc/uic) processes.
> Is there a reason to not use libuv?
>
> 3) Abandon the idea to parallelize AUTOMOC/UIC
>
> Well, I liked the idea.
>
>
> Any thoughts?
>
> -Sebastian
>
> --
>
> Powered by 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-developers
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://cmake.org/pipermail/cmake-developers/attachments/20180108/5540abec/attachment.html>