Re: 2.6.12 Performance problems

From: Danial Thom
Date: Sun Aug 21 2005 - 16:47:08 EST




--- Patrick McHardy <kaber@xxxxxxxxx> wrote:

> Danial Thom wrote:
> > I just started fiddling with 2.6.12, and
> there
> > seems to be a big drop-off in performance
> from
> > 2.4.x in terms of networking on a
> uniprocessor
> > system. Just bridging packets through the
> > machine, 2.6.12 starts dropping packets at
> > ~100Kpps, whereas 2.4.x doesn't start
> dropping
> > until over 350Kpps on the same hardware
> (2.0Ghz
> > Opteron with e1000 driver). This is pitiful
> > prformance for this hardware. I've
> > increased the rx ring in the e1000 driver to
> 512
> > with little change (interrupt moderation is
> set
> > to 8000 Ints/second). Has "tuning" for MP
> > destroyed UP performance altogether, or is
> there
> > some tuning parameter that could make a
> 4-fold
> > difference? All debugging is off and there
> are
> > no messages on the console or in the error
> logs.
> > The kernel is the standard kernel.org dowload
> > config with SMP turned off and the intel
> ethernet
> > card drivers as modules without any other
> > changes, which is exactly the config for my
> 2.4
> > kernels.
>
> Do you have netfilter enabled? Briging
> netfilter was
> added in 2.6, enabling it will influence
> performance
> negatively. Otherwise, is this performance drop
> visible in other setups besides bridging as
> well?
>

Yes, bridging is clean. I also routed with the
same performance drop.

Danial


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