[CMake] CMake Project Generation Speedup

[Robert Maynard]

A round of performance improvements to generate time was done as part
of CMake 3.11 and that significantly helped. What would be helpful is
a performance analysis run of CMake itself to determine if the issue
is that we are IO bound ( and need to do multi-threaded writes ) or
compute bound.

While this information will be project dependent, it would be great to
start getting samples from the community.

On Wed, Mar 20, 2019 at 1:53 PM J. Caleb Wherry <calebwherry at gmail.com> wrote:
>
> Did anything ever come of this?
>
> I am in a similar boat: we have >800 targets on our full build (native C++, Managed C++, C#, Java, CUDA, etc) and the majority of the time for the configure/generate steps takes place in the generate step (>70%).
>
> I understand there is a lot of IO since the generate step has to write the project files and filters for each C++ project (the majority of our projects) for VS generators (what we use). I'm just looking to see if there is anything to look at or potentially speedup up the generate step besides "get a faster drive".
>
> Thanks!
> -Caleb
>
> On Thu, Nov 17, 2016 at 11:15 AM Damian <damian.campeanu at gmail.com> wrote:
>>
>> Hi all,
>>
>> We are still in the process of switching our large Make-based build to CMake. One of the issues we're running into is the time it takes to reparse and regenerate the CMake project (whether ninja, VS, or make) after touching any CMake file. To give you an idea, we have about 1000 targets and that takes a good 2 min for CMake to rerun.
>>
>> Are there any plans to speed this up? Maybe parallelize it in some way or do a better job regenerating only what needs regenerating? Is there anything we can do on our side to reduce our regeneration times?
>>
>> For example, if using a VS generator, each directory in the source that has a CMakeLists.txt gets a .vcproj and .sln generated. Ideally, if I touch one of those CMakeLists.txt, only that .sln/.vcproj would get regenerated.
>>
>> Thanks for any help.
>> --
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>
>
> --
> J. Caleb Wherry
> Scientific Software Engineer
>
> http://www.calebwherry.com
> +1 (615) 708-5651
> calebwherry at gmail.com
> --
>
> 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
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