Bad routing performance on 500Mhz Geode LX with CURRENT,
ipfw and mpd5 (was: ipfw,
"ip|all" proto and PPPoE -- does PPPoE packets passed to ipfw?)
Luigi Rizzo
rizzo at iet.unipi.it
Thu Aug 30 20:54:50 UTC 2012
On Thu, Aug 30, 2012 at 03:32:25PM -0500, Adam Vande More wrote:
> On Thu, Aug 30, 2012 at 4:11 AM, Lev Serebryakov <lev at freebsd.org> wrote:
>
> > Hello, Ian.
> > You wrote 30 ??????? 2012 ?., 10:23:56:
> >
> > >> Yep, I'll collapse my two-rule chains in one rule.
> > IS> I guess if the issue persists, we may need to see more of your ruleset.
> > Not a problem at all, here it is:
> > http://lev.serebryakov.spb.ru/_sklad/firewall.ipfw
> >
> > IS> Hmm, you shouldn't see ANY pppoe traffic on ng0, only on the interface
> > IS> mpd5 uses to connect with your DSL modem/bridge. Nor would you expect
> > Yep. I didn't see it. My question is, really: why vr1 (my physical
> > interface, used to connect to my ISP) takes 50%+ of CPU when traffic
> > is only 40mbit/s down and about 20mbit/s up (with many connections)?
>
>
> Have you taken this into account from vr(4)?
I was indeed going to mention something like this.
Old/slow machines often have very low memory bandwidth,
so the rule 1GHz<->1 Gbit/s does not really apply.
cheers
luigi
> BUGS
> The vr driver always copies transmit mbuf chains into longword-aligned
> buffers prior to transmission in order to pacify the Rhine chips. If
> buffers are not aligned correctly, the chip will round the supplied
> buffer address and begin DMAing from the wrong location. This buffer
> copying impairs transmit performance on slower systems but cannot be
> avoided. On faster machines (e.g. a Pentium II), the performance
> impact
> is much less noticeable.
> --
> Adam Vande More
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