7.1-PRERELEASE : bad network performance (nfe0)

Gary Palmer gpalmer at freebsd.org
Sun Sep 28 20:53:01 UTC 2008

On Sun, Sep 28, 2008 at 01:43:12PM -0400, firmdog at gmail.com wrote:
> I have the same problem on a Dell Poweredge SC440 when I transferred over
> 50GB
> from a FreeBSD 5.4 box to my new Dell running 7.1.  Used a crossover cable
> and
> the link was 1000 full duplex, but could only get about 10M/s.  Very odd.
> Did a
> tcpdump and saw lots of bad checksum errors.
> What other troubleshooting steps can we take?  What could be the problem?

Please post the first few lines of ifconfig for bge0.  I'm suspecting
you'll see something like


(yes, I know thats an em, not bge, but I don't have any bge's around

Note that the options line say that receive and transmit checksum
offloading is enabled.  This means that for packets transmitted
by this system, tcpdump will show checksum errors as the kernel
is not generating the checksums, the ethernet card will.  Since
tcpdump is seeting the packet before the ethernet card does its
magic, you get the checksum errors on transmit.  Received packets
should be fine though.



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