Re: Packages using more than their assigned MAKE_JOBS

Jonathan Perkin <[email protected]> writes:

> The issue is py-scikit-build-core which is the build system for this.
> It delegates to cmake and ninja, and ninja ultimately uses all cores
> by default (and when building 4 versions of py-duckdb simultaneously
> in bulk builds, 4x all cores on the host, plus all the other builds,
> which is enough to kill jenkins.jar for me a few times...)

I must be missing something.

It seems obvious that ninja should run 1 thread only, unless it has been
given an argument that means -jN (however ninja spells it).   And, that
if cmake is invoked, it use 1 thread and ask all child make-type
programs to use only 1 thread, unless cmake was given an explicit
argument that means -jN.

Is ninja deciding to use hw.ncpu or something as a default, but only
when run under cmake under scikit-build, because of some environment
var, or ?  Ninja called from cmake, normally, seems to get this right.