sched_ule(4)

sched_ule4

Ule scheduler

Usage

options SCHED_ULE

Overview

The sched_ule scheduler is an experimental scheduler that provides a number of advanced scheduler features not present in sched_4bsd(4), the default system scheduler. These features address SMP and interactivity and include:

  • Thread CPU affinity.

  • CPU topology awareness, including for hyper-threading.

  • Per-CPU run queues.

  • Interactivity heuristics that detect interactive applications and schedules them preferentially under high load.

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.

The sched_ule scheduler is disabled by default as it is experimental. See the BUGS section for more information.

History

The sched_ule scheduler first appeared in FreeBSD 5.1.

Authors

Jeff Roberson ⟨[email protected]⟩

Bugs

As an experimental scheduler, sched_ule is not enabled by default due to a number of known issues, including weak performance with several known workloads, and reports of instability. Deployment of sched_ule in production environments should be done cautiously.

From freebsd-manpages 6.0-5 in Debian 4.0 (Etch). Parsed by carta from the page's mdoc source.