Re: Quick Fair Queue scheduler maturity and examples

[Eric Dumazet <eric.dumazet@gmail.com>]

Le jeudi 27 octobre 2011 à 14:46 +0200, Karel Rericha a écrit :

> Actually I am doing some reseach to replace our main shaping machine
> with 60 000+ htb classes, which now saturates 12 core Xeon Westmere to
> 30% (there are five gigabit network ports on each interface affinited
> to cores). AFAIK QFQ should be O(1) complexity so it would bring
> saturation a requirements for number of cores down considerably (HTB
> has O(log(N)) complexity).
> 
> I have test machine and about two months to decide if we will stay
> with HTB or we will try something else. So it would be VERY helpful,
> if you would search you memory instead your dead disk :-) and send me
> some example of QFQ usage, if I can ask for a little of your time. I
> promise to have results published here in return.
> 
> Thanks, Karel
> 

That seems a good challenge to me ;)

First upgrade to a recent kernel with QFQ included.
Also upgrade iproute2 to a recent enough version as well.

Then you discover "tc  ... qfq help" is not that helpful :(

# tc qdisc add dev eth3 root qfq help
Usage: ... qfq

OK, its parameters are :

	qfq weight num1 [maxpkt BYTES]

You should not touch maxpkt, its default value being 2048

Oh well, I just tried the obvious and my (remote) machine doesnt answer
to me anymore...

Time for a bit of debugging I am afraid :(