Re: Extremely slow network with e1000 & ip_conntrack

[David S. Miller]

On Thu, 04 Dec 2003 21:36:09 +0900
Stephen Lee <mukansai@xxxxxxxxxxxxx> wrote:

> "Feldman, Scott" <scott.feldman@xxxxxxxxx> wrote:
> > 
> > Try turning off TSO by disabling this code or by using "ethtool -K tso
> > off" (need version 1.8).
> 
> Yes, turning off TSO with ethtool fixed it (tested on 2.6.0-test11).  At
> least we have a workaround now.
> 
> Thanks Scott, Harald and Dave.
> 
> Is it not supported by the hardware?  Seems TSO could improve
> performance a bit since the 1000/MT Desktop is starved for PCI bandwidth
> at 32-bit/33MHz.

This workaround explains everything.  The TSO packets have to be
"un-TSO'd" in order for netfilter to look at the packet and parse
the contents.  This means copying all the data around, allocating
several networking buffers, etc.
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