[altq:1895] Re: CBQ: small pakets are too limited !

[Emmanuel Duros <emmanuel.duros@udcast.com>]

On Wed, 2003-08-20 at 08:46, Kenjiro Cho wrote:
> Emmanuel Duros wrote:
> > I have a router based on FreeBSD 4.4R with altq-3.0.
> > 
> > My router is dedicated to route udp traffic that is shaped with altq. My
> > problem is that I have not been able to shape correctly udp traffic
> > composed of small packets (e.g. 50 to 500 byte-long). The outgoing
> > traffic is significantly below the bandwidth set in altq.conf.
> > 
> > However, when I increase the packet size, I can reach the correct
> > bandwidth.
> 
> This indicates that the CPU is saturated.

I have checked with top and the CPU seems rather. Its is 80% idle, I
have mainly interrupts since the box receives lots of small packets.

> It might help to increase the minburst and the maxburst parameters to
> process more packets at a time. 

The best results I have had are with "minburst 1", the conf file looks
like:

interface xl0 bandwidth 10000000 cbq
class cbq xl0 root_class NULL pbandwidth 100
class cbq xl0 def_class root_class pbandwidth 100 default
class cbq xl0 udp_class def_class exactbandwidth 2400000 maxdelay 1000
minburst 1 
	filter xl0 udp_class 0 0 0 0 17

The UDP traffic is now limited to 2.11Mbps instead of 1.7Mbps. I have
also played with maxburst and it was unsuccessful. If I increase
minburst the througput drops down significantly...

Anymore hints to reach the 2.4Mbps as I would expect ? Need to change
some peaces of code probably ?

Thanks,
> 
> -Kenjiro
-- 
Emmanuel Duros                  http://www.udcast.com
2455 Route des Dolines BP355  | Tel : +33 (0)4 93 00 16 60
06906 Sophia Antipolis France | Fax : +33 (0)4 93 00 16 61
            ** Full IP over Broadcast Media **