Hi Jijiang, On 01/21/2015 09:01 AM, Liu, Jijiang wrote: >>> I still don't understand why you are so eager to 'forbid' it. >>> Yes we support it for FVL, but no one forces you to use it. >> >> Well, how would you describe this 2 ways of doing the same thing in the >> offload API? Would you talk about the i40e registers? It's not because i40e >> has 2 ways to do the same operation that the DPDK should do the same. >> >> How will you explain to a user how to choose between these 2 cases? > > Talk about B method in > http://dpdk.org/ml/archives/dev/2014-December/009213.html again. > > DPDK Never supports a NIC that can recognize tunneling packet for TX side > before 1.8, right?
When you say "recognize tunnel", if you mean offlading checksum of tunnel headers, I agree. If you mean recognizing a tunnel packet in rx, I also agree it's new to dpdk-1.8, but I think it's unrelated to what we are talking about, which is tx checksum. A DPDK application is able to generate tunnel packets by itself and offload the checksums to the NIC. > So when we need to support TX checksum offload for tunneling packet, and we > have to choose B.2. I don't see why we should choose either B.1 or B.2 (I guess you want to say B.1 here, right?). The m->lX_len are not filled in rx today. If one day they are, it won't prevent the application to configure the lX_len fields and offload flags according to the API. > After introducing i40e(FVL), FVL is able to recognize tunneling packet and > support outer IP, or inner IP or outer IP and inner IP TX checksum for > tunneling packet. > And you agree on "outer and inner at the same time", why do you object "only > inner"? > > Actually, B.2 method is a software workaround using L2 length when NIC can't > recognize tunneling packet. > When NIC is able to recognize tunneling packet, I think you shouldn't take > B.2 as a standard to 'forbid' other method. Again, I'm not sure there is a link between "recognizing tunneling packets" and tx checksum offload of tunnels. Regards, Olivier
