[ofa-general] Re: IPoIB forwarding

[Michael S. Tsirkin]

> Quoting Bryan Lawver <lawver1 at llnl.gov>:
> Subject: Re: IPoIB forwarding
> 
> I don't think this sequence should occur.  My IP links have MTU of 9k and I 
> have set the ib0 links to the same MTU.

Not sure about this: IPoIB has different encapsulation header size.
Maybe make IPoIB MTU bigger?

> This sequence of 17k size packet 
> every eighth packet seems to match my retransmit sequence as captured by 
> tcpdump on the IP end of an iperf.  The MSS in the IP header is 8960 so 
> this would seem to be one complete IP packet and the data payload from a 
> second.
> 
> 
> Apr 26 08:30:27 wopr0 ib0: sending packet: head 0x177 length 9004 
> connection 0x340406
> Apr 26 08:30:27 wopr0 ib0: sending packet: head 0x178 length 9004 
> connection 0x340406
> Apr 26 08:30:27 wopr0 ib0: sending packet: head 0x179 length 9004 
> connection 0x340406
> Apr 26 08:30:27 wopr0 ib0: sending packet: head 0x17a length 17964 
> connection 0x340406
> Apr 26 08:30:27 wopr0 ib0: sending packet: head 0x17b length 9004 
> connection 0x340406
> Apr 26 08:30:27 wopr0 ib0: sending packet: head 0x17c length 9004 
> connection 0x340406
> Apr 26 08:30:27 wopr0 ib0: sending packet: head 0x17d length 9004 
> connection 0x340406
> Apr 26 08:30:27 wopr0 ib0: sending packet: head 0x17e length 9004 
> connection 0x340406
> Apr 26 08:30:27 wopr0 ib0: sending packet: head 0x17f length 9004 
> connection 0x340406
> Apr 26 08:30:27 wopr0 ib0: sending packet: head 0x180 length 9004 
> connection 0x340406
> Apr 26 08:30:27 wopr0 ib0: sending packet: head 0x181 length 9004 
> connection 0x340406
> Apr 26 08:30:27 wopr0 ib0: sending packet: head 0x182 length 17964 
> connection 0x340406
> Apr 26 08:30:27 wopr0 ib0: sending packet: head 0x183 length 9004 
> connection 0x340406
> Apr 26 08:30:27 wopr0 ib0: sending packet: head 0x184 length 9004 
> connection 0x340406
> 

I see you have enabled DEBUG_DATA for IPoIB CM - this will hurt performance.

-- 
MST