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

Abdul Rahim, Faizal
2025-02-13T06:12:57Z

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.

I’m really hoping that fpe + mqprio doesn’t have to be enabled together in
this series to keep things simple. It could be added later—adding it now
would introduce additional complexity and delay this series further, which
is focused on enabling basic, working fpe on i226.

Would that be okay with you?