Re: RFC: softint-based if_input

[Joerg Sonnenberger <joerg%britannica.bec.de@localhost>]

On Thu, Jan 14, 2016 at 07:19:03PM +0900, Ryota Ozaki wrote:
> One possible objection should be performance
> degradation, however I believe we can mitigate
> by introducing polling packet processing
> like Linux and FreeBSD do. Of course, we also
> have to rethink existing sofint (L3 softints
> and bridge_forward softint).

While I agree with the goal and also that fast-forward shouldn't stop
this, I would like to see some numbers for the performance impact under
load and maybe the latency change without load. Any chance to test for
that?

> BTW, this proposal includes another change;
> move bpf_mtap to a common place, not doing it
> in each driver. This change is also needed by
> the above proposal to ensure to always run bpf
> in softint.

Be careful, there are multiple BPF hooks in some drivers, e.g. the
WiFi stack.

Joerg