Bug#534430: linux-image-2.6.26: CBQ broken
Bounded classes are allowed to borrow at least under some circumstances.
In my config there is a bounded class parented to root on my DSL uplink
and a hierarchy sitting under it where most classes are allowed to
borrow. If the root class is bounded it all works like a breeze. I have
used to use a replica of this setup under BSD for nearly 10 years and
recently moved it to Linux.
Because the root class was borrowing the underlying hierarchy was
exceeding their allocated bandwidths on casual basis. As a result - no
QoS.
I have worked around it by bringing down the bandwidth of the parent
root CBQ qdisc at the moment. It is now still borrowing:
class cbq 2:16 parent 2: rate 380000bit (bounded) prio 2
Sent 1041746585 bytes 7852722 pkt (dropped 0, overlimits 0 requeues 0)
rate 0bit 0pps backlog 0b 0p requeues 0
borrowed 7984534 overactions 0 avgidle 78 undertime 0
However, it just gets dropped by the qdisc.
Bounded classes in lower levels in the hierarchy actually work. Putting
a few more classes between the root and the first class that is bounded
does not. Overall, it is broken and broken pretty badly.
I have not had the time to sit down and read the actual code yet to see
exactly where it is broken. Apologies,
Best Regards,
On Sat, 2009-07-25 at 22:30 +0200, Moritz Muehlenhoff wrote:
> On Wed, Jun 24, 2009 at 10:21:05AM +0100, Anton Ivanov wrote:
> > Package: linux-image-2.6.26
> > Version: nfsfix.1
> > Severity: normal
> >
> >
> > CBQ is completely broken. The borrowed counters never increase
> > and from there on the bandwidth computation is totally fubar
>
> Please explain the problem more verbosely. What exactly did you
> do and what result did you expect?
>
> Cheers,
> Moritz
>
--
Understanding is a three-edged sword:
your side, their side, and the truth. --Kosh Naranek
A. R. Ivanov
E-mail: aivanov@sigsegv.cx
WWW: http://www.sigsegv.cx/
pub 1024D/DDE5E715 2002-03-03 Anton R. Ivanov <arivanov@sigsegv.cx>
Fingerprint: C824 CBD7 EE4B D7F8 5331 89D5 FCDA 572E DDE5 E715
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