Re: Quick Fair Queue scheduler maturity and examples

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

Le jeudi 27 octobre 2011 à 18:08 +0200, Eric Dumazet a écrit :
> 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 :(

Never mind, it was an user error :)

Here is what I used during my tests, I guess you can adapt your
scripts...

DEV=eth3
RATE="rate 40Mbit"
TNETS="10.2.2.0/25"
ALLOT="allot 20000"

tc qdisc del dev dummy0 root 2>/dev/null

tc qdisc add dev $DEV root handle 1: cbq avpkt 1000 rate 1000Mbit \
	bandwidth 1000Mbit
tc class add dev $DEV parent 1: classid 1:1 \
	est 1sec 8sec cbq allot 10000 mpu 64 \
	rate 1000Mbit prio 1 avpkt 1500 bounded

# output to test nets :  40 Mbit limit
tc class add dev $DEV parent 1:1 classid 1:11 \
	est 1sec 8sec cbq $ALLOT mpu 64      \
	$RATE prio 2 avpkt 1400 bounded

tc qdisc add dev $DEV parent 1:11 handle 11:  \
	est 1sec 8sec qfq

tc filter add dev $DEV protocol ip parent 11: handle 3 \
	flow hash keys rxhash divisor 8

for i in `seq 1 8`
do
 classid=11:$(printf %x $i)
 tc class add dev $DEV classid $classid qfq 
 tc qdisc add dev $DEV parent $classid pfifo limit 30
done

for privnet in $TNETS
do
	tc filter add dev $DEV parent 1: protocol ip prio 100 u32 \
		match ip dst $privnet flowid 1:11
done

tc filter add dev $DEV parent 1: protocol ip prio 100 u32 \
	match ip protocol 0 0x00 flowid 1:1

iperf -u -c 10.2.2.1 -P 32 -l 50