Would the problem with queue lengths also exist if CONFIG_HZ=1000 in .config? (it certainly improves latency) I've configured rates from 10kbit/s...2Mbit/s on one machine, so changing the kernel code "for low rates" would probably effect the high rates too. Or, in other words, what is exactly the problem with an SFQ length of 128 for low rates? Cheers, Jeroen. On Thu, 25 Mar 2004 17:17:44 +1100 "Andrew Hall" <temp02@xxxxxxxxxxxxxxx> 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. > > ----- Original Message ----- > From: "Simon Byrnand" <simon@xxxxxxxxxxx> > To: "Jeroen Vriesman" <j.vriesman@xxxxxxxxx>; <lartc@xxxxxxxxxxxxxxx> > Sent: Thursday, March 25, 2004 4:36 PM > Subject: Re: HTB speed > > > > At 11:14 14/03/2004, Jeroen Vriesman wrote: > > >Hi, > > > > > >just putting the answer to my own question here, for those who have the > > >same problem, and read the mailing list archive. > > > > > >The timing of the P4 based on "jiffies" is hopeless, it's different for > > >every processor, and can be a wrong by a factor 3. > > > > > >If the tsc (time stamp counter) is used, the htb works fine, the error in > > >speed is now only about 1 %. > > > > > >It's set by: > > > > > >in pkt_sched.h: > > > > > >#define PSCHED_CLOCK_SOURCE PSCHED_CPU > > > > > >that's all, I wonder why it's not default to do this, or maybe it's an > > >idea to make the packet scheduler detect the presence of tsc when the > > >module is loaded. > > > > Hi, > > > > Which pkt_sched.h are you refering to ? > > /usr/src/linux/include/linux/pkt_sched.h or > > /usr/src/linux/include/net/pkt_sched.h ? > > > > And after changing it what did you do ? Recompile the kernel ? > > > > Or recompile tc ? > > > > I too see the same problems with htb (very poor accuracy of speed, > > significantly too slow, also very jerky) while cbq is very accurate and > > smooth. (But lacks some features I need) > > > > Regards, > > Simon > > > > _______________________________________________ > > LARTC mailing list / LARTC@xxxxxxxxxxxxxxx > > http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/ > > _______________________________________________ > LARTC mailing list / LARTC@xxxxxxxxxxxxxxx > http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/ > _______________________________________________ LARTC mailing list / LARTC@xxxxxxxxxxxxxxx http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/
