7.1-PRERELEASE : bad network performance (nfe0)

[Jeremy Chadwick]

On Sun, Sep 28, 2008 at 06:15:43PM -0400, firmdog at gmail.com wrote:
> On Sun, Sep 28, 2008 at 4:53 PM, Gary Palmer <gpalmer at freebsd.org> wrote:
> 
> > 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
> >
> > em1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
> >        options=1b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING>
> >
> > (yes, I know thats an em, not bge, but I don't have any bge's around
> >  here)
> >
> > 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.
> >
> > Regards,
> >
> > Gary
> >
> 
> 
> Pasted below.  When I was doing the transfer, it was 1000 full duplex and
> was very slow.
> This is a web/email/database server and I don't see any performance problems
> yet, but
> I would like to know what the problem is/was.  What else can I provide?
> 
> bge0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
>         options=9b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM>
>         ether 00:1a:a0:23:c0:03
>         inet 192.168.1.2 netmask 0xffffff00 broadcast 192.168.1.255
>         media: Ethernet autoselect (100baseTX <full-duplex>)
>         status: active

I see 100baseTX there, not 1000baseTX.  This speed is being selected via
autoneg (auto speed/duplex negotiation).

Whatever switch you're connected to is not properly negotiating the
speed.

What brand and model of switch is this host connected to, and are you
*absolutely certain* it supports (and is configured for) gigE?

-- 
| Jeremy Chadwick                                jdc at parodius.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |