HFSC latency control

HFSC latency control

[Santi]

If this is not the correct place to ask these questions, please let me 
know if you know about any forum, mailing list, IRC channel or wherever 
HFSC questions could be asked and answered.

I have read some HFSC theory and some old messages in the archive of 
this mailing list. I am testing HFSC in my lab. Traffic is correctly 
shaped but I do not get the expected results regarding latency.

tc qdisc add dev eth0 root handle 1: hfsc default 90
tc class add dev eth0 parent 1:0 classid 1:1 hfsc ls m2 100kbps ul m2 
100kbps
tc class add dev eth0 parent 1:1 classid 1:10 hfsc rt m1 50kbps d 100 m2 
10kbps
tc class add dev eth0 parent 1:1 classid 1:20 hfsc ls m2 70kbps
tc class add dev eth0 parent 1:1 classid 1:90 hfsc ls m2 10kbps
tc filter add dev eth0 protocol ip parent 1:0 prio 1 u32 match ip src 
192.168.10.0/24 flowid 1:10
tc filter add dev eth0 protocol ip parent 1:0 prio 1 u32 match ip src 
192.168.20.0/24 flowid 1:20

I expected to have the lowest latency on packets from 192.168.10.0/24, 
however they get much more delayed than any other traffic.

What am I doing wrong?

I would like to have one example where I can see HFSC controls latency. 
I have seen lots of theory but very few examples, and when I test them 
in my lab I don't see the expected results regarding latency.

I generate traffic with Ostinato and test latency with ping and qperf.