GSP
Quick Navigator

Search Site

Unix VPS
A - Starter
B - Basic
C - Preferred
D - Commercial
MPS - Dedicated
Previous VPSs
* Sign Up! *

Support
Contact Us
Online Help
Handbooks
Domain Status
Man Pages

FAQ
Virtual Servers
Pricing
Billing
Technical

Network
Facilities
Connectivity
Topology Map

Miscellaneous
Server Agreement
Year 2038
Credits
 

USA Flag

 

 

Man Pages


Manual Reference Pages  -  GSCHED (8)

NAME

gsched - control utility for disk scheduler GEOM class

CONTENTS

Synopsis
Description
Sysctl Variables
Exit Status
Examples
See Also
History
Authors

SYNOPSIS

gsched create [-v] [-a algorithm] provider ... gsched insert [-v] [-a algorithm] provider ... gsched configure [-v] [-a algorithm] node ... gsched destroy [-fv] node ... gsched reset [-v] node ... gsched { list | status | load | unload }

DESCRIPTION

The gsched utility (also callable as geom sched ...) changes the scheduling policy of the requests going to a provider.

The first argument to gsched indicates an action to be performed:
create Create a new provider and geom node using the specified scheduling algorithm. algorithm is the name of the scheduling algorithm used for the provider. Available algorithms include: rr, which implements anticipatory scheduling with round robin service among clients; as, which implements a simple form of anticipatory scheduling with no per-client queue.

If the operation succeeds, the new provider should appear with name /dev/<dev.sched.>. The kernel module geom_sched.ko will be loaded if it is not loaded already.

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.

A subsequent "destroy" will remove the newly created geom and hook the provider back to the original geom.

configure
  Configure existing scheduling provider. It supports the same options as the create command.
destroy Destroy the geom specified in the parameter.
reset Do nothing.
list | status | load | unload
  See geom(8).

Additional options:
-f Force the removal of the specified provider.
-v Be more verbose.

SYSCTL VARIABLES

The following sysctl(8) variables can be used to control the behavior of the SCHED GEOM class. The default value is shown next to each variable.
kern.geom.sched.debug: 0
  Debug level of the 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.

EXIT STATUS

Exit status is 0 on success, and 1 if the command fails.

EXAMPLES

The following example shows how to create a scheduling provider for disk /dev/ada0, and how to destroy it.
# 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.

SEE ALSO

geom(4), geom(8)

HISTORY

The gsched utility first appeared in
.Fx 8.1 .

AUTHORS


.An Fabio Checconi Aq fabio@FreeBSD.org
.An Luigi Rizzo Aq luigi@FreeBSD.org
Search for    or go to Top of page |  Section 8 |  Main Index


Powered by GSP Visit the GSP FreeBSD Man Page Interface.
Output converted with manServer 1.07.