tc-hfsc(8)

NAME#

HFSC - Hierarchical Fair Service Curve's control under linux

SYNOPSIS#

tc qdisc add ... hfsc [ \ndefault\n CLASSID ]
tc class add ... hfsc [ [ \nrt\n SC ] [ \nls\n SC ] | [ \nsc\n SC ] ] [ \nul\n SC ]
\nrt\n : realtime service curve
\nls\n : linkshare service curve
\nsc\n : rt+ls service curve
\nul\n : upperlimit service curve
• at least one of \nrt\n, \nls\n or \nsc\n must be specified
• \nul\n can only be specified with \nls\n or \nsc

SC := [ [ m1 BPS ] d SEC ] m2 BPS

bash

m1\n : slope of the first segment
\nd\n  : x-coordinate of intersection
\nm2\n : slope of the second segment

SC := [ [ umax BYTE ] dmax SEC ] rate BPS

bash

umax\n : maximum unit of work
\ndmax\n : maximum delay
\nrate\n : 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: <[email protected]>

AUTHOR#

Manpage created by Michal Soltys ([email protected])