Re: [PATCH v2 3/5] rust: driver: Add ACPI id table support to Adapter trait

[Danilo Krummrich <dakr@kernel.org>]

On 6/6/25 5:29 PM, Greg Kroah-Hartman wrote:
> On Fri, Jun 06, 2025 at 03:26:13PM +0100, Igor Korotin wrote:
>> On Fri, Jun 6, 2025 at 2:50 PM Danilo Krummrich <dakr@kernel.org> wrote:
>>> However, I don't understand why we need this and the subsequent
>>> is_acpi_device_node() and is_of_node() checks.
>>
>> The idea is to avoid unnecessary table lookups when both OF and ACPI
>> match tables are present. If we already know the fwnode type, these
>> simple pointer comparisons (is_acpi_device_node() / is_of_node()) let
>> us skip the irrelevant match function.
>>
>> Those checks are cheap (just pointer comparisons), while
>> acpi_match_device() and of_match_device() iterate over tables.
>>
>> So yeah, it’s a bit ugly, but it can save some CPU cycles during enumeration.
> 
> You have loads of CPU cycles during enumeration, keep things simple
> first, only attempt to optimize things later on if it is actually
> measureable.

I'm fine either way, I don't expect much value in optimizing this and at the
same time I don't see doing it adds significant complexity either.

If Greg prefers not to have this optimization to begin with, let's go without
it please.