On Thu, 4 Oct 2018 08:44:27 +0200 Björn Töpel <bjorn.topel@xxxxxxxxx> wrote: > Den tors 27 sep. 2018 kl 02:56 skrev Rob Sherwood <rob.sherwood@xxxxxxxxx>: > > > > Thanks for the reference and the page-per-packet point makes sense. > > At the same time, not supporting jumbo frames seems like a non-trivial > > limitation. Are there a subset of drivers that do support jumbo > > frames (or LRO or the other features that require multiple pages per > > packet)? > > > > No, not at the moment. XDP has a strict "one frame cannot exceed a > page" constraint. Everything that applies to XDP in terms of > constraints, applies to AF_XDP as well. > > Just to clarify, XDP supports jumbo frames -- i.e. larger than 1500B > payload, just not the maximum 9000B size. My personal observation is > that many deployments that "require jumbo frames", are usually OK with > an of MTU ~3000B. Jumbo frames, yes. Full jumbo frames, no. :-) Thank you for clarifying that Bjørn. Can Alex or Rob explain: (1) What is your use-case for wanting jumbo-frames? And (2) will an MTU of ~3000Bytes be sufficient? (which XDP does support) > > On Tue, Sep 25, 2018 at 9:44 AM Alex Forster <aforster@xxxxxxxxxxxxxx> wrote: > > > > > > > On my test box running 4.18 if XDP is in use the MTU can not be > > > > set higher than 3050. > > > > > > Ah, that answers a few questions for me. Thanks! > > > > > > Alex Forster -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer
|