On Mon, 9 Dec 2019 at 16:00, Toke Høiland-Jørgensen <toke@xxxxxxxxxx> wrote: > > Björn Töpel <bjorn.topel@xxxxxxxxx> writes: > [...] > > I like the new version where it's integrated into bpf_prog_run_xdp(); > nice! :) > Yes, me too! Nice suggestion! > > The XDP dispatcher is always enabled, if available, because it helps > > even when retpolines are disabled. Please refer to the "Performance" > > section below. > > Looking at those numbers, I think I would moderate "helps" to "doesn't > hurt" - a difference of less than 1ns is basically in the noise. > > You mentioned in the earlier version that this would impact the time it > takes to attach an XDP program. Got any numbers for this? > Ah, no, I forgot to measure that. I'll get back with that. So, when a new program is entered or removed from dispatcher, it needs to be re-jited, but more importantly -- a text poke is needed. I don't know if this is a concern or not, but let's measure it. Björn > -Toke >
