Re: [Intel-wired-lan] [PATCH iwl-next 07/12] idpf: compile singleq code only under default-n CONFIG_IDPF_SINGLEQ

[Jacob Keller]

On 5/28/2024 6:48 AM, Alexander Lobakin wrote:
> Currently, all HW supporting idpf supports the singleq model, but none
> of it advertises it by default, as splitq is supported and preferred
> for multiple reasons. Still, this almost dead code often times adds
> hotpath branches and redundant cacheline accesses.
> While it can't currently be removed, add CONFIG_IDPF_SINGLEQ and build
> the singleq code only when it's enabled manually. This corresponds to
> -10 Kb of object code size and a good bunch of hotpath checks.
> idpf_is_queue_model_split() works as a gate and compiles out to `true`
> when the config option is disabled.
> 

Could you clarify why we can't remove it? Presumably there exist some
users out there who depend on this (and can thus set the CONFIG option)?
Or is it because we intend to support some hardware which only supports
singleq sometime soon?

This is a huge improvement over leaving it as-is, but I do wonder why
not just completely remove it. Its also a surprisingly small patch, but
I guess thats because the singleq_txrx is a separate file.