freebsd-skq/lib/geom/sched/gsched.8
Brooks Davis e4b0a90e77 Normalize the g(eom,cache,part,...) build.
Rather then combining hardlink creation for the geom(8) binary with
shared library build, move libraries to src/lib/geom so they are
built and installed normally.  Create a common Makefile.classes
which is included by both lib/geom/Makefile and sbin/geom/Makefile
so the symlink and libraries stay in sync.

The relocation of libraries allows libraries to be build for 32-bit
compat.  This also reduces the number of non-standard builds in
the system.

This commit is not sufficent to run a 32-bit /sbin/geom on a 64-bit
system out of the box as it will look in the wrong place for libraries
unless GEOM_LIBRARY_PATH is set appropriatly in the environment.

Reviewed by:	bdrewery
Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D15360
2018-06-25 19:55:15 +00:00

163 lines
4.6 KiB
Groff

.\" Copyright (c) 2009-2010 Fabio Checconi
.\" Copyright (c) 2009-2010 Luigi Rizzo, Universita` di Pisa
.\" 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 July 26, 2012
.Dt GSCHED 8
.Os
.Sh NAME
.Nm gsched
.Nd "control utility for disk scheduler GEOM class"
.Sh SYNOPSIS
.Nm
.Cm create
.Op Fl v
.Op Fl a Ar algorithm
.Ar provider ...
.Nm
.Cm insert
.Op Fl v
.Op Fl a Ar algorithm
.Ar provider ...
.Nm
.Cm configure
.Op Fl v
.Op Fl a Ar algorithm
.Ar node ...
.Nm
.Cm destroy
.Op Fl fv
.Ar node ...
.Nm
.Cm reset
.Op Fl v
.Ar node ...
.Nm
.Cm { list | status | load | unload }
.Sh DESCRIPTION
The
.Nm
utility (also callable as
.Nm geom sched ... )
changes the scheduling policy of the requests going to a provider.
.Pp
The first argument to
.Nm
indicates an action to be performed:
.Bl -tag -width ".Cm configure"
.It Cm create
Create a new provider and geom node using the specified scheduling algorithm.
.Ar algorithm
is the name of the scheduling algorithm used for the provider.
Available algorithms include:
.Ar rr ,
which implements anticipatory scheduling with round robin service
among clients;
.Ar as ,
which implements a simple form of anticipatory scheduling with
no per-client queue.
.Pp
If the operation succeeds, the new provider should appear with name
.Pa /dev/ Ns Ao Ar dev Ac Ns Pa .sched. .
The kernel module
.Pa geom_sched.ko
will be loaded if it is not loaded already.
.It Cm insert
Operates as "create", but the insertion is "transparent",
i.e. the existing provider is rerouted to the newly created geom,
which in turn forwards requests to the existing geom.
This operation allows one to start/stop a scheduling service
on an already existing provider.
.Pp
A subsequent "destroy" will remove the newly created geom and
hook the provider back to the original geom.
.It Cm configure
Configure existing scheduling provider. It supports the same options
as the
.Nm create
command.
.It Cm destroy
Destroy the geom specified in the parameter.
.It Cm reset
Do nothing.
.It Cm list | status | load | unload
See
.Xr geom 8 .
.El
.Pp
Additional options:
.Bl -tag -width ".Fl f"
.It Fl f
Force the removal of the specified provider.
.It Fl v
Be more verbose.
.El
.Sh SYSCTL VARIABLES
The following
.Xr sysctl 8
variables can be used to control the behavior of the
.Nm SCHED
GEOM class.
The default value is shown next to each variable.
.Bl -tag -width indent
.It Va kern.geom.sched.debug : No 0
Debug level of the
.Nm SCHED
GEOM class.
This can be set to a number between 0 and 2 inclusive.
If set to 0 minimal debug information is printed, and if set to 2 the
maximum amount of debug information is printed.
.El
.Sh EXIT STATUS
Exit status is 0 on success, and 1 if the command fails.
.Sh EXAMPLES
The following example shows how to create a scheduling provider for disk
.Pa /dev/ada0 ,
and how to destroy it.
.Bd -literal -offset indent
# Load the geom_sched module:
kldload geom_sched
# Load some scheduler classes used by geom_sched:
kldload gsched_rr
# Configure device ada0 to use scheduler "rr":
geom sched insert -a rr ada0
# Now provider ada0 uses the "rr" algorithm;
# the new geom is ada0.sched.
# Remove the scheduler on the device:
geom sched destroy -v ada0.sched.
.Ed
.Sh SEE ALSO
.Xr geom 4 ,
.Xr geom 8
.Sh HISTORY
The
.Nm
utility first appeared in
.Fx 8.1 .
.Sh AUTHORS
.An Fabio Checconi Aq Mt fabio@FreeBSD.org
.An Luigi Rizzo Aq Mt luigi@FreeBSD.org