Re: [PATCH net-next 0/2] net: Use SMP threads for backlog NAPI (or optional).

[Sebastian Andrzej Siewior]

Sorry, getting back that late, I was traveling the last two weeks…

On 2023-10-09 18:09:37 [-0700], Jakub Kicinski wrote:
> On Sat, 7 Oct 2023 17:59:57 +0200 Sebastian Andrzej Siewior wrote:
> > Apologies if I misunderstood. You said to make it optional which I did
> > with the static key in the second patch of this series. The first patch
> > is indeed not what we talked about I just to show what it would look
> > like now that there is no "delay" for backlog-NAPI on the local CPU.
> > 
> > If the optional part is okay then I can repost only that patch against
> > current net-next.
> 
> Do we have reason to believe nobody uses RPS?

Not sure what you relate to. I would assume that RPS is used in general
on actual devices and not on loopback where backlog is used. But it is
just an assumption.
The performance drop, which I observed with RPS and stress-ng --udp, is
within the same range with threads and IPIs (based on memory). I can
re-run the test and provide actual numbers if you want.

Sebastian