Conan: [cmake helper] CONAN_CPU_COUNT is not respected with the ninja generator

[niosHD]

Conan Version: 1.18.4

I just upgraded some of our projects to build with ninja by setting CONAN_CMAKE_GENERATOR=Ninja. While everything still works, this change caused quite a high load on the CI runner that I was not really expecting.

In particular, it seems like the cmake helper is ignoring the configured CONAN_CPU_COUNT value when the ninja generator is used. See:

https://github.com/conan-io/conan/blob/0882a2a8c85b848b277aa45893576a45e208e27e/conans/client/build/cmake.py#L238

I would expect that also the ninja generator adheres to the specified cpu count.

[czoido]

Hi @niosHD ,
Maybe you could add custom arguments for the CMake build using something like this in the conanfile.py:
def build(self): cmake = CMake(self) cmake.configure() cmake.build(args=["--", "-j1"])
To reduce number of maximum commands you want Ninja to run in parallel.
Please tell us if this helps :)

[memsharded]

Hi @niosHD

Yes, this makes sense, the Ninja generator is not receiving any parallel argument, only Makefiles and Visual. This should be added, thanks for pointing this out.