TCP differences in 7.2 vs 7.1

[Pyun YongHyeon]

On Wed, May 13, 2009 at 10:52:34AM +1200, Nigel Wohlers wrote:
> On 13/5/09 8:41 AM, Xin LI wrote:
> >-----BEGIN PGP SIGNED MESSAGE-----
> >Hash: SHA1
> >
> >Hi David,
> >
> >David Samms wrote:
> >>After upgrading to 7.2 (amd64) some customers complained of very poor
> >>bandwidth.  Upon investigation all the effected customers were ATT DSL
> >>clients located all over the USA, not in a single city, nor were other
> >>ISPs effected.  The server is a Supermicro with  dual (quad core)
> >>processors with a single Intel fxp network card on a 100mbit connection.
> >
> >Could you please try if this would help:
> >
> >	sysctl net.inet.tcp.tso=0
> >
> >Cheers,
> >- --
> >Xin LI<delphij at delphij.net>	http://www.delphij.net/
> 
> 
> Thank you!  This hint has saved me a lot of troubleshooting.
> 
> I was having the same issue as David with 3 servers recently upgraded to 
> 7.2.  Clients (MS Windows) were complaining that they were having 
> intermittent connectivity issues talking to these servers (https, imaps).
> 
> They too have fxp network interface cards, no issues with other servers 
> upgraded to 7.2 with em cards.
> 

Instead of disabling TSO in network stack, just disable TSO in
fxp(4) as a workaround. Fix already is in RELENG_7(r191867) so you
can extract the patch and apply it by hand if you want.

For instance,
#cd /tmp
#fetch -o fxp.tso.patch "http://svn.freebsd.org/viewvc/base/head/sys/dev/fxp/if_fxp.c?r1=190982&r2=188176&view=patch"
#cd /usr/src/sys/dev/fxp
#patch -p4 < /tmp/fxp.tso.patch
And rebuild kernel.