Re: [PATCH v2 2/4] knownnetworks: sort known frequencies by BSS rank

[James Prestwood <prestwoj@gmail.com>]

On 1/24/24 10:44 AM, Denis Kenzior wrote:
> Hi James,
>
>>> Perhaps an easier way to accomplish this would be to add known 
>>> frequencies in reverse bss->rank sorted order.  That way last seen 
>>> frequency with best ranked BSS would be first?
>>
>> I'm not sure I understand, how would this be any different than just 
>> reversing
>
> Well, right now we maintain the least recently seen frequency list in 
> a very simple way:
>
> - When scan results become available
>     - Walk the result list (which is sorted by bss_rank?)
>     - Add each result's frequency to the frequency cache
>         - Remove any matching entry in the cache
>         - Add it to head
>
> Since the result list is sorted, the top entry in the frequency cache 
> is the least ranked.  This doesn't matter for small networks since 
> there would only be a couple results.
>
> What we should do is to add the frequencies to the frequency cache in 
> reverse order.  That way the highest ranked bss is at the top of the 
> frequency cache.

Oh I see, I didn't realize the list was already sorted since its coming 
from network->bss_list. But wouldn't we have the same problem here? Old 
frequencies with a high rank would remain at the front unless they were 
seen by a recent scan. So if you saw a really high ranked AP once then 
never again it would always stay at the front.

Another thing I didn't consider is multiple BSS's on the same frequency :)

Maybe introducing a last seen time would help, though that adds even 
more complication.

>
> Hope that made sense.
>  Regards,
> -Denis
>