[xdp-hints] Re: Interest in TX-side XDP metadata hints from Intel (+ Red Hat)

["Song, Yoong Siang" <yoong.siang.song@intel.com>]

On Thursday, September 21, 2023 12:36 PM, Stanislav Fomichev <sdf@google.com> wrote:
>On Wed, Sep 20, 2023 at 7:10 PM Song, Yoong Siang
><yoong.siang.song@intel.com> wrote:
>>
>> On Friday, September 15, 2023 5:06 AM, Stanislav Fomichev <sdf@google.com>
>wrote:
>> >On Wed, Sep 13, 2023 at 6:22 PM Song, Yoong Siang
>> ><yoong.siang.song@intel.com> wrote:
>> >>
>> >> On Saturday, September 9, 2023 12:38 AM Stanislav Fomichev
>> ><sdf@google.com> wrote:
>> >> >On Fri, Sep 8, 2023 at 7:18 AM Jesper Dangaard Brouer
>> >> ><hawk@kernel.org>
>> >> >wrote:
>> >> >>
>> >> >> Hi Stanislav,
>> >> >>
>> >> >> Sharing that Intel (+Red Hat) have an interest in getting XDP
>> >> >> metadata hints working on smaller devices used for "Edge
>> >> >> Controls for
>> >Industrial"
>> >> >> (ECI)[1].
>> >> >>
>> >> >> What are your plans for your patchset[2] ?
>> >> >
>> >> >Sorry, I was OOO for two weeks and then got distracted by some
>> >> >internal work :- ( I'll probably post another respin next week. I
>> >> >think I've addressed most of the Maciej's feedback, but the only
>> >> >thing that we need to move this forward is to support another
>> >> >device besides mlx5. Maciej was suggesting ice, but I don't have
>> >> >the hw :-( I have some idfp-capable devices, so I'll probably try
>> >> >to play with it instead (but
>> >the idpf driver is still not pulled).
>> >> >
>> >> >So if you want to help speed it up, we should probably focus first
>> >> >on getting some of the intel nics support tx metadata.
>> >> >To proceed, maybe I should post my next iteration and we can
>> >> >collaborate on the ice driver changes?
>> >> >Who should I CC explicitly?
>> >> >
>> >> Hi Stanislav,
>> >>
>> >> I can help to speed it up. I don't have ice HW on my hand as well,
>> >> so maybe we can start with igc drivers, followed by stmmac drivers.
>> >>
>> >> Please post your next iteration, then we can collaborate based on that.
>> >
>> >Awesome, thanks! The v2 is out, you're on the CC. Feel free to reach
>> >out directly if you have any questions or suggestions.
>>
>> Hi Stanislav,
>>
>> Thanks for the v2. I do have one question. What is the code base which you are
>using?
>> When I try to apply your v2 patch set on top of latest net-next, there
>> are few merge conflicts, and it seem like Rx Metadata is not included in your
>base.
>
>Anything prior to my recent commit "bpf: make it easier to add new metadata
>kfunc" should work. That's most likely the reason it conflicts.
>So try to cherry pick it on top of the following and let me know if you still have an
>issue; I can rebase and repost:
>5c04433daf9e - bpf: Charge modmem for struct_ops trampoline (6 days
>ago) <Song Liu>

This base work for me. Thanks.
Btw, how we should collaborate?
After done coding and testing on my side, I send you my patches, 
then you will include them into your patchset v3? 

>
>Regarding rx metadata: it's separate from af_xdp and it's more generically
>implemented in the xdp layer, see:
>Documentation/networking/xdp-rx-metadata.rst
>
>Also see tools/testing/selftests/bpf/prog_tests/xdp_metadata.c for an example
>on how to use both rx and tx sides.
>
>> Thanks & Regards
>> Siang
>>
>> >
>> >I also have to abaon my idea of playing with idpf since the driver
>> >that's posted on the list doesn't have af_xdp support :-(
>> >
>> >
>> >> Thanks & Regards
>> >> Siang
>> >>
>> >> >> My suggestion (to Intel) is that we implement the TX-timestamp
>> >> >> (plus
>> >> >> LaunchTime) on top of Stanslav's patches[2].  For drivers
>> >> >> igc+igb+stmmac which I think will cover the tests[3] need by
>> >> >> Arun/Costin (?). And then post it upstream for review.
>> >> >>
>> >> >> The Intel test tool[3] isn't open, but it is an AF_XDP based
>> >> >> Real-Time Compute Performance (RTCP) application that show-case
>> >> >> a real-time control loop application.  The current code uses
>> >> >> out-of-tree[4]
>> >"TXTIME"
>> >> >> LaunchTime feature, that want not upstreamed.
>> >> >>
>> >> >> Lets us instead implement a proper TX LaunchTime feature on top of [2].
>> >> >>
>> >> >> --Jesper
>> >> >> cc. XDP-hints ML as anyone is free to code this up, code help
>> >> >> here[5]
>> >> >>
>> >> >>
>> >> >> [1] https://eci.intel.com/
>> >> >> [2]
>> >> >> https://lore.kernel.org/all/20230809165418.2831456-1-sdf@google.
>> >> >> com / [3] https://github.com/OTCShare2/rtcp-xdp
>> >> >> [4] https://lore.kernel.org/all/20210621230635.3a83851c@carbon/
>> >> >> [5]
>> >> >> https://github.com/xdp-project/xdp-project/blob/master/areas/tsn
>> >> >> /co
>> >> >> de0
>> >> >> 1_follow_qdisc_TSN_offload.org#tx-time-to-hardware-driver-igc