Toshiaki Makita <toshiaki.makita1@xxxxxxxxx> writes: > On 19/10/23 (水) 2:45:05, Toke Høiland-Jørgensen wrote: >> John Fastabend <john.fastabend@xxxxxxxxx> writes: >> >>> I think for sysadmins in general (not OVS) use case I would work >>> with Jesper and Toke. They seem to be working on this specific >>> problem. >> >> We're definitely thinking about how we can make "XDP magically speeds up >> my network stack" a reality, if that's what you mean. Not that we have >> arrived at anything specific yet... >> >> And yeah, I'd also be happy to discuss what it would take to make a >> native XDP implementation of the OVS datapath; including what (if >> anything) is missing from the current XDP feature set to make this >> feasible. I must admit that I'm not quite clear on why that wasn't the >> approach picked for the first attempt to speed up OVS using XDP... > > Here's some history from William Tu et al. > https://linuxplumbersconf.org/event/2/contributions/107/ > > Although his aim was not to speed up OVS but to add kernel-independent > datapath, his experience shows full OVS support by eBPF is very > difficult. Yeah, I remember seeing that presentation; it still isn't clear to me what exactly the issue was with implementing the OVS datapath in eBPF. As far as I can tell from glancing through the paper, only lists program size and lack of loops as limitations; both of which have been lifted now. The results in the paper also shows somewhat disappointing performance for the eBPF implementation, but that is not too surprising given that it's implemented as a TC eBPF hook, not an XDP program. I seem to recall that this was also one of the things puzzling to me back when this was presented... -Toke
