HFSC
Section: Linux (8)
Updated: 31 October 2011
Page Index
NAME
HFSC - Hierarchical Fair Service Curve's control under linux
SYNOPSIS
tc qdisc add ... hfsc [ default CLASSID ]
tc class add ... hfsc [ [ rt SC ] [ ls SC ] | [ sc SC ] ] [ ul SC ]
rt : realtime service curve
ls : linkshare service curve
sc : rt+ls service curve
ul : upperlimit service curve
• at least one of rt, ls or sc must be specified
• ul can only be specified with ls or sc
- SC := [ [ m1 BPS ] d SEC ] m2 BPS
- m1 : slope of the first segment
d : x-coordinate of intersection
m2 : slope of the second segment
- SC := [ [ umax BYTE ] dmax SEC ] rate BPS
- umax : maximum unit of work
dmax : maximum delay
rate : rate
For description of BYTE, BPS and SEC - please see
UNITS
section of
tc(8).
DESCRIPTION (qdisc)
HFSC qdisc has only one optional parameter -
default. CLASSID specifies
the minor part of the default classid, where packets not classified by other
means (e.g. u32 filter, CLASSIFY target of iptables) will be enqueued. If
default is not specified, unclassified packets will be dropped.
DESCRIPTION (class)
HFSC class is used to create a class hierarchy for HFSC scheduler. For
explanation of the algorithm, and the meaning behind
rt,
ls,
sc and
ul service curves - please refer to
tc-hfsc(7).
As you can see in SYNOPSIS, service curve (SC) can be specified in two
ways. Either as maximum delay for certain amount of work, or as a bandwidth
assigned for certain amount of time. Obviously, m1 is simply
umax/dmax.
Both m2 and rate are mandatory. If you omit other
parameters, you will specify linear service curve.
SEE ALSO
tc(8),
tc-hfsc(7),
tc-stab(8)
Please direct bugreports and patches to: <netdev@vger.kernel.org>
AUTHOR
Manpage created by Michal Soltys (
soltys@ziu.info)