1.\" Copyright (c) 2005 Robert N. M. Watson 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD$ 26.\" 27.Dd April 7, 2005 28.Os 29.Dt SCHED_ULE 4 30.Sh NAME 31.Nm sched_ule 32.Nd ULE Scheduler 33.Sh SYNOPSIS 34.Cd "options SCHED_ULE" 35.Sh DESCRIPTION 36.Nm 37is an experimental scheduler that provides a number of advanced scheduler 38features not present in 39.Xr sched_4bsd 4 , 40the default system scheduler. 41These features address SMP and interactivity and include: 42.Pp 43.Bl -bullet -compact -offset indent 44.It 45Thread CPU affinity. 46.It 47CPU topology awareness, including for hyper-threading. 48.It 49Per-CPU run queues. 50.It 51Interactivity heuristics that detect interactive applications and schedules 52them preferentially under high load. 53.El 54.Pp 55The following sysctls are relevant to the operation of 56.Nm : 57.Bl -tag -width indent 58.It kern.sched.name 59This read-only sysctl reports the name of the active scheduler. 60.El 61.Pp 62.Nm 63is disabled by default as it is experimental. 64See the bugs section for more information. 65.Sh SEE ALSO 66.Xr sched_4bsd 4 , 67.Xr sysctl 8 68.Sh HISTORY 69The 70.Nm 71scheduler first appeared in 72.Fx 5.1 . 73.Sh AUTHORS 74.An Jeff Roberson 75.Aq jeff@FreeBSD.org 76.Sh BUGS 77As an experimental scheduler, 78.Nm 79is not enabled by default due to a number of known issues, including weak 80performance with several known workloads, and reports of instability. 81Deployment of 82.Nm 83in production environments should be done cautiously. 84