At 12:46 26/03/2004, Simon Byrnand wrote:
At 18:17 25/03/2004, Andrew Hall wrote:
You need to recompile the kernel after altering this value in
linux/include/net/pkt_sched.h. Also remember that if using SFQ on leaf
qdisc, then the queue length may cause delay problems if it's too long
(default is 128). Changing this to 32 for rates below 100kb/s, I have found
to help things considerably. This change needs to be done in
linux/net/sched/sch_sfq.c. which also needs a kernel recompilation.
Hmm,
When I use sfq with cbq at speeds like 256Kbit there is no problem at all, runs very sweetly, but with HTB and sfq, it is very jerky and poor. I'll try the change in pkt_sched.h first and see how I go...
Ok, I tried the change in pkt_sched.h and didn't notice any difference whatsoever. Any other ideas ? cbq is still fine but htb for the same speed is very jerky and the speed fluctuates around 60-80% of the wanted speed, while cbq gives a steady 99% of the wanted speed...
You can make HTB more accurate by setting HTB_HYSTERESIS to 0 in net/sched/sch_htb.c.
To save time - if you built HTB as a module, you can probably (well it worked for me) get away with editing htb.c and do
make SUBDIRS=net/sched modules
and replacing /lib/modules/[kversion]/kernel/net/sched/htb.o with the new htb.o from your source tree.
If you are doing it live stop shaping and check with lsmod that modprobe -r gets rid (do it again if it's still there) of the old htb.o and reload shaping scripts.
Make sure the quantum is your mtu, set 0 burst for bulk classes and don't set perturb too low on sfq (I use 20 as it causes packet reordering).
Are you shaping egress or ingress and how are you measuring speed?
Andy.
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