Jan-Bernd Themann wrote: > On Monday 30 July 2007 22:32, Andrew Gallatin wrote:
>> Second, you still need to set skb->ip_summed = CHECKSUM_UNNECESSARY >> when modified packets are flushed, else the stack will see bad >> checksums for packets from CHECKSUM_COMPLETE drivers using the >> skb interface. Fixed in the attached patch. > > I thought about it... As we do update the TCP checksum for aggregated > packets we could add a second ip_summed field in the net_lro_mgr struct > used for aggregated packets to support HW that does not have any checksum > helper > functionality. These drivers could set this ip_summed field to CHECKSUM_NONE, > and thus leave the checksum check to the stack. I'm not sure if these old > devices benefit > a lot from LRO. So what do you think? This might be handy, and it would also fix the problem with CHECKSUM_PARTIAL drivers using the skb interface by allowing them to set it to CHECKSUM_UNNECESSARY. >> Fourth, I did some traffic sniffing to try to figure out what's going >> on above, and saw tcpdump complain about bad checksums. Have you tried >> running tcpdump -s 65535 -vvv? Have you also seen bad checksums? >> I seem to see this for both page- and skb-based versions of the driver. >> > > Hmmm, can't confirm that. For our skb-based version I see > correct checksums for aggregated packets and for the page-based version as > well. > I used: (tcpdump -i ethX -s 0 -w dump.bin) in combination with ethereal. > Don't see problems as well with your tcpdump command. I'm still trying to get a handle on this. It happens both with page based and skb based receive for me.. I would not be surprised if I was doing something wrong in myri10ge. But I don't see it without LRO, or with my LRO. I'll let you know when I figure it out.. In the meantime, in case you have any insight, I've left a capture of a small "netcat" transfer of a 64KB file full of zeros at http://www.myri.com/staff/gallatin/lro/netcat_dump.bz2 Drew _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
