On Sat, Mar 06, 2004 at 08:07:51PM +0059, Jedi/Sector One wrote:
> Hello.
>
> Is there any rule of thumb in order to find out the right value for the
> qlength knob of cbq schedulers?
>
> I have to restrict the outgoing traffic to 110 Mb/s on a gigabit link.
>
> The default value of qlength is 50 and pfctl -vvsq shows that this value
> is often almost reached and the 'suspends' counter increases.
i was wondering about this too. i wonder if they act differently between
cbq and hfsc...
one perception i have is that this number defines how many possible packets
can be in the queue at once. the queue is flushed at a specific fixed
interval, and if another packet tries to get in the queue, it is suspended
out. raising this number would help work around that.
the other perception i have is that this number defines the quantity of
packets which, when reached, trigger a flush of the queue, or 'dequeue'
them like i saw mentioned a lot when i was trying to find info on HFSC...
giving me the idea that when this # is reached, pf will then organize
the packets in the queue as per your priorities/bandwidths, and then
be ready for the next ${qlimit} # of packets. lessening the qlimit would
then allow for a faster, 'quicker turnover' of the queueingness.
the first paragraph seems to lean towards how cbq works, the second towards
how hfsc works....
when i use hsfc, without red, i don't get a 'suspend' counter; just
dropped packets/bytes - and it doesn't really seem to drop them unless
i use 'red'. i was then seeing red as a way to guard against a queue
using full bandwidth percent ( or at least making it exponentially
difficult for that to happen as the limit of bandwidth allocation for
the queue was approached ); but since i am trying to setup the queues
to be OK with all of them at full util, i've dropped 'red' out of there
and have been happy with the results so far...
problem is i am twiddling knobs i don't know much about <G>
jared
--
[ openbsd 3.4 GENERIC ( feb 27 ) // i386 ]
