SCHED_ULE(4)

📦 version 15.1, in freebsd 14.5, freebsd 15.1, nixpkgs unstable

SCHED_ULE(4) — ULE scheduler 💅

okay so bestie, this is the SCHED_ULE(4) page from the Kernel Interfaces Manual, and we're talking about the ULE scheduler. it's giving main character energy, fr fr — we are obsessed, no cap. 🦋

✨ NAME ✨

sched_ule — ULE scheduler

✨ SYNOPSIS ✨

options SCHED_ULE

💖 DESCRIPTION 💖

okay so the sched_ule scheduler provides a number of advanced scheduler features not present in sched_4bsd(4), the traditional system scheduler. these features address SMP and interactivity and include:

  • Thread CPU affinity. 🧵 your thread can have a fave CPU, lowkey.
  • CPU topology awareness, including for hyper-threading. 🖥️ it knows the vibes of your CPU layout — vibe check passed.
  • Per-CPU run queues. 👑 each CPU gets its own little queue moment.
  • Interactivity heuristics that detect interactive applications and schedules them preferentially under high load. 🔥 under high load, interactive apps get prioritized — periodt.

the following sysctls are relevant to the operation of sched_ule:

kern.sched.name

this read-only sysctl reports the name of the active scheduler. it's literally just telling you which scheduler is the main character rn, ngl. 💅

kern.sched.quantum

this read-write sysctl reports or sets the length of the quantum (in micro-seconds) granted to a thread. yes bestie, read it and write it — highkey iconic, iykyk. 🎀

🌈 SEE ALSO 🌈

🌸 HISTORY 🌸

the sched_ule scheduler first appeared in FreeBSD 5.1. periodt. ✨

👑 AUTHORS 👑

Jeff Roberson <jeff@FreeBSD.org> 🫶

source/version: Debian · date: August 10, 2012 · SCHED_ULE(4) 💖

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