Astro Hacker News - Apple XNU: Clutch Scheduler

trueno |next [-]

interesting. id love an eclecticlight breakdown of this. they're one of the few if only that write anything worth reading on apple hardware, i once found a QOS/scheduler insight through those guys when I couldn't get my c/cpp project pinned to the cores I wanted on m-series. https://eclecticlight.co/m1-macs/

cadamsdotcom |next |previous [-]

> The XNU kernel runs on a variety of platforms

This is fascinating, would love to know where it’s used! (Besides macOS)

csb6 |root |parent |next [-]

I believe it means Apple's other hardware platforms (phones, tablets, smart TVs, VR headsets, smartwatches)

electronsoup |root |parent |previous [-]

Perhaps they mean ISAs

xphos |root |parent |next [-]

Well x86 at one point, arm both the 32 and 64 bit versions. I think they had RISCV support in their source tree at one point but not really at a commercial level. It does cover a lot different levels of hardware though

LoganDark |root |parent |previous [-]

IIRC, Apple uses 'platform' to refer to an SoC integration. For example, M1, M2 and etc. are separate platforms. M5 in Vision Pro is a separate platform than M5 in MacBook Pro. I believe Apple's XNU does somewhat still support non-Apple Silicon as well though.

almoni |previous [-]

Does this contribute to macOS's suitability for DAW applications or is that more the baked in low-latency audio drivers?

dcrazy |root |parent |next [-]

Audio actually runs on a dedicated realtime thread. This used to be scheduled differently, but nowadays it might be implemented by the FIXPRI bucket described in this document.

bigyabai |root |parent |previous [-]

CoreAudio probably deserves most of the credit, there. Similar ASIO-style solutions like JACK, DirectSound and now Pipewire hit the sub-30ms mark without any big scheduler tweaks.