freebsd-nq/share/man/man4/sched_ule.4
Simon L. B. Nielsen 4517aab293 - 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.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $FreeBSD$
.\"
.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.