freebsd-skq/share/man/man4/sched_ule.4
simon 440a3866d6 - Remove SCHED_ULE from GENERIC to better avoid foot-shooting by
unsuspecting users.
- Add a comment in NOTES about experimental status of SCHED_ULE.
- Make warning about experimental status in sched_ule(4) a bit
  stronger.

Suggested and reviewed by:	dougb
Discussed on:			developers
MFC after:			3 days
2006-10-05 20:31:58 +00:00

91 lines
2.7 KiB
Groff

.\" Copyright (c) 2005 Robert N. M. Watson
.\" All rights reserved.
.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
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.\" $FreeBSD$
.\"
.Dd April 7, 2005
.Os
.Dt SCHED_ULE 4
.Sh NAME
.Nm sched_ule
.Nd ULE scheduler
.Sh SYNOPSIS
.Cd "options SCHED_ULE"
.Sh DESCRIPTION
The
.Nm
scheduler
is an experimental scheduler that provides a number of advanced scheduler
features not present in
.Xr sched_4bsd 4 ,
the default system scheduler.
These features address SMP and interactivity and include:
.Pp
.Bl -bullet -compact -offset indent
.It
Thread CPU affinity.
.It
CPU topology awareness, including for hyper-threading.
.It
Per-CPU run queues.
.It
Interactivity heuristics that detect interactive applications and schedules
them preferentially under high load.
.El
.Pp
The following sysctls are relevant to the operation of
.Nm :
.Bl -tag -width indent
.It Va kern.sched.name
This read-only sysctl reports the name of the active scheduler.
.El
.Pp
The
.Nm
scheduler
is disabled by default as it is experimental.
See the
.Sx BUGS
section for more information.
.Sh SEE ALSO
.Xr sched_4bsd 4 ,
.Xr sched_core 4 ,
.Xr sysctl 8
.Sh HISTORY
The
.Nm
scheduler first appeared in
.Fx 5.1 .
.Sh AUTHORS
.An Jeff Roberson
.Aq jeff@FreeBSD.org
.Sh BUGS
As an experimental scheduler,
.Nm
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
.Nm
in production environments is not recommended at this time.