Re: [PATCH iwl-next v4 0/9] igc: Add support for Frame Preemption feature in IGC

Abdul Rahim, Faizal
2025-02-13T12:54:29Z

On 13/2/2025 8:01 pm, Kurt Kanzenbach wrote:
> On Thu Feb 13 2025, Abdul Rahim, Faizal wrote:
>> On 13/2/2025 6:01 am, Vladimir Oltean wrote:
>>> On Mon, Feb 10, 2025 at 02:01:58AM -0500, Faizal Rahim wrote:
>>>> Introduces support for the FPE feature in the IGC driver.
>>>>
>>>> The patches aligns with the upstream FPE API:
>>>> https://patchwork.kernel.org/project/netdevbpf/cover/20230220122343.1156614-1-vladimir.oltean@nxp.com/
>>>> https://patchwork.kernel.org/project/netdevbpf/cover/20230119122705.73054-1-vladimir.oltean@nxp.com/
>>>>
>>>> It builds upon earlier work:
>>>> https://patchwork.kernel.org/project/netdevbpf/cover/20220520011538.1098888-1-vinicius.gomes@intel.com/
>>>>
>>>> The patch series adds the following functionalities to the IGC driver:
>>>> a) Configure FPE using `ethtool --set-mm`.
>>>> b) Display FPE settings via `ethtool --show-mm`.
>>>> c) View FPE statistics using `ethtool --include-statistics --show-mm'.
>>>> e) Enable preemptible/express queue with `fp`:
>>>> tc qdisc add ... root taprio \
>>>> fp E E P P
>>>
>>> Any reason why you are only enabling the preemptible traffic classes
>>> with taprio, and not with mqprio as well? I see there will have to be
>>> some work harmonizing igc's existing understanding of ring priorities
>>> with what Kurt did in 9f3297511dae ("igc: Add MQPRIO offload support"),
>>> and I was kind of expecting to see a proposal for that as part of this.
>>>
>>
>> I was planning to enable fpe + mqprio separately since it requires extra
>> effort to explore mqprio with preemptible rings, ring priorities, and
>> testing to ensure it works properly and there are no regressions.
>
> Well, my idea was to move the current mqprio offload implementation from
> legacy TSN Tx mode to the normal TSN Tx mode. Then, taprio and mqprio
> can share the same code (with or without fpe). I have a draft patch
> ready for that. What do you think about it?
>
> Thanks,
> Kurt

Hi Kurt,

I’m okay with including it in this series and testing fpe + mqprio, but I’m
not sure if others might be concerned about adding different functional
changes in this fpe series.

Hi Vladimir,
Any thoughts on this ?