Re: AF_XDP (i40e) behavior change in 5.11?

[Magnus Karlsson <magnus.karlsson@gmail.com>]

On Thu, Mar 25, 2021 at 11:17 PM Dan Siemon <dan@coverfire.com> wrote:
>
> On Wed, 2021-03-24 at 11:00 +0100, Magnus Karlsson wrote:
> > On Wed, Mar 24, 2021 at 10:22 AM Dan Siemon <dan@coverfire.com>
> > wrote:
> > >
> > > ./xsk_fwd -i ens1f0 -q 2 -i ens1f1 -q 2 -c 5 -i ens1f0 -q 3 -i
> > > ens1f1 -
> > > q 3 -c 6
> > >
> > > On 5.10, the cores (2,3) assigned interrupts for the queues (2,3)
> > > are
> > > idle when there is no traffic.
> > >
> > > On 5.11, the cores immediately go to 100% system time when the
> > > program
> > > starts (as viewed in htop). There is no network traffic.
> > >
> > > Intel 710/i40e.
> > >
> > > I tried this with xsk_fwd built from 5.10 and 5.11 trees with the
> > > same
> > > result.
> > >
> > > Is this behavior change expected?
> >
> > Thanks for reporting this. No, this is not intentional. I did send up
> > a fix for a bug in the i40e driver that was introduced in 5.11. It
> > might be the culprit. Could you please try the patch below and see if
> > it works? It is not yet in net.
> >
> > https://www.spinics.net/lists/netdev/msg729128.htm
>
> Hi Magnus,
>
> It appears (quick testing) that the patch fixes the problem.

Perfect! I will send a mail and try to get it through the internal
testing as soon as possible so we can get it up on the list and
merged.

Thank you: Magnus

> Thanks.
>