Intel 82550 Pro/100 Ethernet and TSO troubles

[Andrea Venturoli]

On 12/14/11 22:32, YongHyeon PYUN wrote:

>> Wireshark showed some wrong checksums (I believe on the ICMP packet, but
>> I might remember wrong).
>
> You can check whether you received bad checksummed frames with
> netstat(1).

I tried "netstat -ind", but it shows no Ierrs/Idrop/Oerrs/Odrop.





> Is simple downloading from client to server is enough to trigger
> the issue?

Yes and no.
Depending on where the client is located (on the Internet) and/or the 
protocol used, I get either failures or ridicuolous performance (i.e. 
58-60kB/s without TSO vs. 1-2kB/s with TSO).





> Packet capture that shows the problem would be great to
> know what's going on here.

I'll send them to you privately.

You'll see tso.dump and notso.dump: they are both from the same client 
downloading the same (random) file (the file name was changed only  to 
prevent possible caching).
See notso.dump is perfect, while tso.dump shows a lot of potential problems.





>> Would you try attached patch and let me know it goes?
> Sorry, it seems extra pull up for TCP payload may not be required
> here.  Try this instead.

I see a little increase in performance (2-3kB/s instead of 1-2kB/s); 
this might however well depend on external factors. Still it is very 
different from what I'm get without TSO.



  bye & Thanks
	av.

P.S. I can live well without TSO; I'm just doing this to let the 
software improve. Go ahead only if *you* are interested.