kern/155736: [pf] [altq] borrow from parent queue does not work with cbq

[Marcin Wisnicki]

>Number:         155736
>Category:       kern
>Synopsis:       [pf] [altq] borrow from parent queue does not work with cbq
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sun Mar 20 23:40:01 UTC 2011
>Closed-Date:
>Last-Modified:
>Originator:     Marcin Wisnicki
>Release:        8.2-STABLE
>Organization:
>Environment:
FreeBSD ghost.pnet.one.pl 8.2-STABLE FreeBSD 8.2-STABLE #1: Wed Mar  2 17:18:23 CET 2011     root at ghost.pnet.one.pl:/home/obj/usr/src/sys/SERWER_DDB  i386

>Description:
I have queues like this:

altq on $lan_if cbq bandwidth 100Mb queue { qLocal, qExt }
queue qLocal bandwidth 0b cbq(default borrow)
queue qExt bandwidth 10Mb cbq { qExtFast, qExtSlow }
queue  qExtFast priority 7 bandwidth 80% cbq(borrow)
queue  qExtSlow priority 1 bandwidth 20% cbq(borrow red)

pass on $lan_if from <slow> to $internet queue qExtSlow
pass on $lan_if from $internet to <slow> queue qExtSlow
pass on $lan_if from !<slow> to $internet queue qExtFast

Lan is 100Mbps and Wan is 10Mbps. Above rules are supposed to slow down traffic coming from internet to <slow> hosts.

Unfortunately it seems that borrowing does not work when parent queue (qExt) does not also borrow. But it should according to man and PF FAQ.
pfctl -sq -v shows 0 packets in qExt. If I reduce eg. qExtFast to 10% it goes down as if there was no borrow.

Googling reveals many similar posts dating back to FreeBSD-6, possibly bug is there since ALTQ introduction.

>How-To-Repeat:

>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: