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Apple XNU: Clutch Scheduler

172 points by tosh

by trueno

2 subcomments

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/

by cadamsdotcom

4 subcomments

> The XNU kernel runs on a variety of platforms
This is fascinating, would love to know where it’s used! (Besides macOS)

by poige

1 subcomments

Darwin had bunch of schedulers except this one: dualq, multiq, etc
In fact here's the one used in Sonoma: sysctl kern.sched -> edge
which seems to be an extension over "clutch":
https://github.com/apple-oss-distributions/xnu/blob/main/osf...
"… Single-cluster, symmetric (SMP) systems can run with just the Clutch policy, but multi-cluster, asymmetric (AMP) systems must further enable the Edge policy extension to Clutch in order to manage scheduling across the multiple CPU clusters. …"

by travisgriggs

0 subcomment

Read through much of this. Definitely started feeling like “a picture might be worth 1,000+ words”.

by almoni

2 subcomments

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

by MarginalGainz

0 subcomment