> Quoting Jason Gunthorpe <[EMAIL PROTECTED]>: > Subject: Re: [ofa-general] [PATCHv2] IB/ipoib: S/G and HW checksum support > > On Thu, Sep 06, 2007 at 09:40:11AM +0300, Or Gerlitz wrote: > > > >Micheal has made it so you can use 'csum offload' (via disabling csum) > > >on any nic. You can also do the same kind of thing for TSO/GSO. If you > > >send jumbo TSO/GSO packets in a chunk the receiver can then do > > >LRO. Win all around. Sort of like jumbo MTU but without actually > > >changing the MTU. > > > > > >This is all basically the same set of techniques we see between a > > >Linux guest and the linux host in a virtualization environment. > > > > Thanks for the clarification, I have to do some catchup here on the > > details re TSO/GSO and their relation to virtualization, however, to > > make things a little clearer to me, do you agree that as James pointed > > over this thread in > > > > A (IB) ---- B (Gateway eg HW based) ---- C (Ethernet) > > > > scheme, in case A does not compute the TCP checksum of a packet, its > > note the role of the gateway to do so, and C would just drop it?! > > I think the proper way to view Michael's patch, and indeed this whole > idea, is that it just moves the work around, with the goal of > eliminating the work for a class of communication (Linux host to Linux > host). So yes, if a gateway uses this feature then it must regenerate > the checksum before it forwards it. > > It is actually a pretty neat idea, I've never heard of another network > doing this. I wouldn't call it hardware checksum, but more like a > peer-to-peer VNIC scheme. Nobody would object if a vnic driver moved > checksum and segmentation offload to the VNIC device over a RC QP, and > I think the same rational for that applies here, except it is now peer > to peer. (Michael maybe that is a good name for this concept: p2p_vnic?)
Yea. Roland, does the argument sound convincing to you? > FWIW, general gateways do have a bit of a problem doing the csum > insertion because there are alot of cases and new protocols do crop up > from time to time. It would be best if part of the information sent in > this case was instructions on how to do the insertion like an general > ethernet chip would use. Not sure I know what do you mean. Could you give an example please? -- MST _______________________________________________ general mailing list [email protected] http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
