From: Andy Furniss <andy.furniss@dsl.pipex.com>
To: lartc@vger.kernel.org
Subject: Re: [LARTC] HTB speed
Date: Fri, 26 Mar 2004 09:27:20 +0000 [thread overview]
Message-ID: <4063F778.4070109@dsl.pipex.com> (raw)
In-Reply-To: <20040312105840.50e8aab4.j.vriesman@prompt.nl>
Simon Byrnand wrote:
> 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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next prev parent reply other threads:[~2004-03-26 9:27 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-03-12 9:58 [LARTC] HTB speed Jeroen Vriesman
2004-03-13 23:14 ` Jeroen Vriesman
2004-03-15 11:37 ` Maria Joana Urbano
2004-03-15 11:55 ` Jeroen Vriesman
2004-03-15 12:04 ` Jeroen Vriesman
2004-03-25 5:36 ` Simon Byrnand
2004-03-25 6:17 ` Andrew Hall
2004-03-25 9:48 ` Jeroen Vriesman
2004-03-25 18:20 ` ThE LinuX_KiD
2004-03-26 0:46 ` Simon Byrnand
2004-03-26 4:27 ` Simon Byrnand
2004-03-26 9:27 ` Andy Furniss [this message]
2004-03-26 19:17 ` Jeroen Vriesman
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