[REQ] Allow selection of E or P cores on Apple Silicon via QoS

[gingerbeardman]

Is your feature request related to a problem? Please describe

On Apple Silicon Macs, apps can run on either Efficiency or Performance cores.

Apps can assign themselves and their processes to either type of core via QoS.

https://eclecticlight.co/2022/01/07/how-macos-controls-performance-qos-on-intel-and-m1-processors/

Describe the solution you'd like

• Option in Keka to select E or P cores only when running on Apple Silicon.

Describe alternatives you've considered

• Cormorant
  https://eclecticlight.co/2020/12/11/cormorant-now-supports-drag-and-drop-and-can-run-ten-times-faster/

[aonez]

Thanks @gingerbeardman. Always interesting to read eclecticlight. Since lately I'm working hard with Swift I've tried a lot of qos on iOS.

Keka is using all the available cores right now (E and P). Using just one of those will result in slower tasks (specially using the E ones). What will be the benefit for you? Or what idea or case of use do you have in mind?

[aonez]

Correction, just checked that compression and extraction of  Archive in Keka is done using only the performance cores.

[gingerbeardman]

It would be great to be able to specify only E cores for power saving. I don't mind it taking longer when battery is more important.

[aonez]

This is the same operation on top running only on efficiency cores and on bottom on all cores. Obviously this is a big file and with the slowest option of 7Z. For smaller files and faster options the difference will not be that big.

[gingerbeardman]

Is the difference less stark when using Apple Archive?

[aonez]

Indeed, the same operation takes 4 seconds on performance and 26 seconds on efficiency. Still amazed with this format.

[gingerbeardman]

Excellent, my M1 MBP is yet to arrive. But I'm ready for it!!!

[aonez]

Still not sure about this. Same test as above (AAR 2.68 file), CPU history and energy impact.

Anyway, here a test version that runs tasks in background priority (efficiency cores on M1). No toggle, just compare it to the regular Keka version: Keka-QoS-9

Efficiency

Performance

[gingerbeardman]

https://twitter.com/howardnoakley/status/1520073629861560325

They’re doing it right, but Energy Impact is junk: at QoS 9, the E cores will be limited to less than 1 GHz, but the Energy Impact graph isn’t aware of that. In general Activity Monitor etc. don’t monitor core frequency yet.

https://twitter.com/howardnoakley/status/1520074477899550721

Also worth noting that no QoS can limit to only P cores - the choice is (P and E) or (E only). Depending on other workload, threads could readily be loaded on E cores even at maximum QoS. They might also benefit from increasing max threads to 10, if not already.

[aonez]

@gingerbeardman when are you receiving your M1 equipped Mac?