Subject: Re: HTB accuracy for high speed

From: Vladimir Ivashchenko <[email-masked]>
Date: Tue, 19 May 2009 17:04:16 +0300

> > Please disregard my comment about HFSC. It still overspills heavily.
> > 
> > On a 400 mbps limit, I'm getting 520 mbps actual throughput.
> 
> I guess you should send some logs. Your previous report seem to show

Can you give some hints on which logs you would like to see?

> the sum of sc rates of of children could be too high. You seem to
> expect the parent's sc and ul should limit this, but actually children
> rates decide and parent's rates are mainly for lending/borrowing (at

The children's ceil rate is 70% of the parent 1:2 class rate.

> least in HTB). So, it would be nice to try with one leaf class first,
> (similarly to Antonio) how high rates are respected.

Unfortunately its difficult for me to play with classes as its real traffic. 
I'll try to get a traffic generator.

> High drop should be OK if the flow is much faster than scheduling/
> hardware send rate. It could be a bit higher than in older kernels
> because of limited requeuing, but this could be corrected with
> longer queue lenghts (sfq has a very short queue: max 127).

I don't think its sfq, since I have the same sfq qdiscs with HSFC.

Also I'm comparing this to my production HTB box has 2.6.21.5 with esfq 
and no bond (just eth), esfq also has 127p limit.

I tried to get rid of bond on the outbound traffic, I balanced traffic
via eth0 and eth2 manually by splitting routes going through them.

I still had the same issue with HTB not reaching the full speed.

I'm going to try testing exactly the same configuration on 2.6.29 as I have
on 2.6.21.5 tonight. The only difference would be that I use sfq(dst) instead of
esfq(dst) which is not available on 2.6.29.

-- 
Best Regards
Vladimir Ivashchenko
Chief Technology Officer
PrimeTel, Cyprus - www.prime-tel.com