fxp: stalled transfers

Pyun YongHyeon pyunyh at gmail.com
Fri Apr 10 00:14:22 UTC 2009

On Thu, Apr 09, 2009 at 11:02:06AM +0200, Bjoern Koenig wrote:
> pyunyh at gmail.com wrote:
> > If you can easily reproduce the issue, can you capture stalled TCP
> > session with tcpdump on receiving host?(Make sure to disable Rx
> > checksum offload prior to capturing the session.)
> I transferred a 256 kiB file and these are the tcpdumps:
> http://www.alpha-tierchen.de/~bkoenig/fxp0-with-tso.txt
> http://www.alpha-tierchen.de/~bkoenig/fxp0-without-tso.txt
> Actually the transfer doesn't stall although ftp and scp told me so. It
> becomes incredibly slow. It seems like that the chunks are too large and a
> smaller packet will be resent. I decreased the MTU from 1500 to 1492 and
> it works fine with TSO enabled.
> I also captured the traffic on my router:
> http://www.alpha-tierchen.de/~bkoenig/fxp0-with-tso-router.txt
> http://www.alpha-tierchen.de/~bkoenig/fxp0-without-tso-router.txt
> It reveals a suspect information: "truncated-ip - 8 bytes missing!"
> I almost suppose that this is a PPPoE-related configuration issue and the
> fxp driver is not necessarily the problem since decreasing the MTU of the
> LAN host solves it.

I think you're right. Thanks a lot!

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