Add an API to allow getting the number of "performance" cores-only

Feature or enhancement

Proposal:

Currently Python provides os.cpu_count() which returns the total number of physical CPU cores.

On macOS M-class machines (and probably other ARM hardware), there are actually two types of CPU cores: performance cores, and efficiency cores.

For many tasks where a user wants to do "1 task per core", it really only makes sense to do 1 task per performance core.

Therefore it'd be sensible to expose this number. On macOS it can be found with the hw.perflevel0.logicalcpu sysctl.

This could be done in one of two ways, a new function, e.g. os.performance_cpu_count(), or as a keyword-argument to os.cpu_count(performance_cores_only=True).

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

No response

Empieza leyendo la API existente os.cpu_count() y sus implementaciones específicas de cada plataforma; después, investiga el sysctl de macOS hw.perflevel0.logicalcpu descrito en la propuesta. Compara las opciones de una nueva función y de un argumento de palabra clave en las plataformas compatibles, e identifica las pruebas relevantes. Se considera terminado cuando la API elegida expone de forma fiable el número de núcleos de rendimiento, con un comportamiento documentado y cobertura para los sistemas compatibles.