Re: XDP multi-buffer and AF_XDP

Hi All,
Does anyone know if any progress has been made with respect to
multi-buffer support with AF_XDP? I would also like to help.

Kal

On Tue, Apr 5, 2022 at 1:12 PM Maciej Fijalkowski
<[email protected]> wrote:
>
> On Fri, Apr 01, 2022 at 09:52:02AM -0400, [email protected] wrote:
> > On Fri, Apr 01, 2022 at 01:26:12PM +0000, Karlsson, Magnus wrote:
> > >
> > >
> > > > -----Original Message-----
> > > > From: Jesper Dangaard Brouer <[email protected]>
> > > > Sent: Friday, April 1, 2022 3:13 PM
> > > > To: Toke Høiland-Jørgensen <[email protected]>; Kal Cutter Conley
> > > > <[email protected]>; Xdp <[email protected]>
> > > > Cc: Brouer, Jesper <[email protected]>; Lorenzo Bianconi
> > > > <[email protected]>; Karlsson, Magnus
> > > > <[email protected]>; [email protected]
> > > > Subject: Re: XDP multi-buffer and AF_XDP
> > > >
> > > >
> > > > On 01/04/2022 13.39, Toke Høiland-Jørgensen wrote:
> > > > > Kal Cutter Conley <[email protected]> writes:
> > > > >
> > > > >>>
> > > > >>> Hi,
> > > > >>> We are very interested in receiving jumbo frames (> 8000 bytes) over
> > > > >>> AF_XDP. Does XDP multi-buffer support XDP_REDIRECT with AF_XDP?
> > > > What
> > > > >>> about in zero-copy mode?
> > > > >>>
> > > > >>> Cheers,
> > > > >>> Kal
> > > > >>
> > > > >> Looking into this more I found this comment in the mlx5 driver:
> > > > >>
> > > > >> /* Don't enable multi buffer on XDP_REDIRECT SQ, as it's not yet
> > > > >> * supported by upstream, and there is no defined trigger to allow
> > > > >> * transmitting redirected multi-buffer frames.
> > > > >> */
> > > > >>
> > > > >> So at least mlx5 does not yet support XDP multi-buffer with
> > > > >> XDP_REDIRECT. What "upstream" support is required to get
> > > > XDP_REDIRECT
> > > > >> to work with XSKs?
> > > > >
> > > > > Well, the initial patch set for multibuf explicitly blocked
> > > > > XDP_REDIRECT between interfaces, which is what that comment is
> > > > > referring to (the TX side).
> > > > >
> > > > > For AF_XDP we'd also need to define the UAPI, and maybe add a socket
> > > > > flag so the userspace program can signal to the kernel that it
> > > > > understands it? Not sure about the details.
> > > > >
> > > > > You're definitely not the only person who wants this, though; adding
> > > > > in some people who may have a better idea of the exact steps needed.
> > > >
> > > > Cc. Eric Sage, as he also expressed interest in implementing this...
> > >
> > > Adding Tirtha that has patches for the AF_XDP support of multi-buffer.
> > > Though, he is currently integrating his i40e multi-buffer driver
> > > support with Lorenzo's TX-patches that he sent as an RFC. Latest I
> > > heard is that Tirtha is planning on submitting this in a couple of
> > > weeks as a proper patch to the mailing list. And after that, the focus
> > > is to brush up the AF_XDP and ZC support patches as we stopped trying
> > > to track Lorenzo's multi-buffer patches at version 13 out of 23 ;-).
> > > We just could not keep up.
> >
> > Ah, if there is anything I can do to help please let me know. My company needs this
> > feature so I can work on it full time. I would love to help out however I can.
>
> Hey Eric! We'll keep you in loop in terms of progress around this work.
>
> >
> > Thanks,
> > Eric Sage
> > >
> > > > --Jesper
> > >