Packet-corruption with re(4)

[Jeremy Chadwick]

On Tue, Apr 29, 2008 at 02:30:27PM +0200, Peter Ankerstål wrote:
>
> On Apr 29, 2008, at 2:08 PM, Jeremy Chadwick wrote:
>>>
>>
>> tcpdump reporting "bad cksum" can occur due to TX/RX checksum
>> offloading.  Do you not see this message normally, but only when the
>> problem begins?
>>
>> Have you tried turning off TX/RX offloading to see if the erroneous
>> behaviour goes away?
>>
>> Have you tried disabling RFC1323 to see if that's actually what's
>> responsible for the stalls you're seeing?  sysctl net.inet.tcp.rfc1323=0
>>
>> I'd recommend staying away from Realtek NICs.  Pick up an Intel Pro/1000
>> GT or PT.  Realtek has a well-known history of issues.
>>
>
> Now Ive tried:
> ninja# sysctl net.inet.tcp.rfc1323=0
> net.inet.tcp.rfc1323: 1 -> 0
> ninja# ifconfig re0 -rxcsum -txcsum -tso -lro
>
> The problem remains, but when I have -rxcsum/tx tcpdump does not say 
> anything
> about bad checksums but it send out the same ack over and over.
> and it seems like bigger files are the most effected (images rather then 
> html-files)

Okay, so the problem is likely not with checksums, but more of a problem
with network I/O suddenly stopping for no apparent reason.

Have you tried disabling MSI/MSI-X via /boot/loader.conf to see if that
makes any difference?  I wonder if somehow interrupts are no longer
firing for the re(4) card.  Try putting these in loader.conf and
rebooting:

hw.pci.enable_msi="0"
hw.pci.enable_msix="0"

Otherwise, I think Pyun YongHyeon might have some better ideas.

-- 
| 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 |