Use better kernel api for P/E-cores

[HenrikHolst]

@wereii found a proper kernel way to check for the presence of P- and E-cores so we don't have to check the frequency differences.

Kept the frequency check in case the kernel way does not exist on the users kernel but upped the fail-safe to 10% from 5% to close #498

closes #498
closes #501

[afayaz-feral]

Thanks, merged!
Ideally the 10% fail-safe won't even be used, as all affected CPUs are Alder Lake and newer.

[HenrikHolst]

Thanks, merged! Ideally the 10% fail-safe won't even be used, as all affected CPUs are Alder Lake and newer.

true but I am unsure on how long the kernel have separated alder lake+ in /sys/ so there might be some older kernels out there without this support.

[afayaz-feral]

That's a good point 🙂
Still annoying that the only documentation I could find was man perf stat

[HenrikHolst]

yep, the real one is probably buried deep in some mail to LKML years ago...