Re: [PATCH RFC 0/7] wifi: cfg80211/mac80211: add support to handle per link statistics of multi-link station

[Ben Greear <greearb@candelatech.com>]

On 1/9/25 20:24, Sarika Sharma wrote:
> Current implementation of NL80211_CMD_GET_STATION does not work
> for multi-link operation(MLO) since in case of MLO only deflink
> (or one of the links) is considered and not all links.
> 
> Hence, add the link_sinfo structure to provide infrastructure
> for link-level station statistics for multi-link operation(MLO).
> 
> Additionally, accumulated stats for MLO are included in a concise
> manner to provide a comprehensive overview of the ML stations.
> 
> NOTE:
>     1. Current code changes are done to get an early feedback on design.
>     2. Once RFC patches are approved will add the required driver changes.
>     3. Ath12k changes are included in this series for reference to other
>        driver changes.

> Alternate approach:
>     - Keep sinfo structure as it is and use this for non-ML or
>       accumulated statistics for ML station.
>     - Add link sinfo for links with only certain link specific statistics.
>     - Keep mac_op_sta_statistics at MLD level and let driver fill the
>       MLO and link level data, if driver not filling let mac80211 fill
>       the data.
>     - Corresponding changes done to embed statistics into the NL message
>       based on the sinfo/link_sinfo.

My suggestions for general approach to this:

1)  current sinfo stats should report totals for all links,
but it should not sum them up at query time because links come
and go.  So driver/firmware/mac80211 or whatever is keeping count
of the stats needs to count the total tx/rx/ packets/bytes/whatever
as it happens.

2)  Per-link stats can be over duration of the link object.

3)  For sinfo logic that currently reports tx/rx mcs rate and such that cannot
be summed, use 'best' link's for those values.  Effectively, this probably means highest
frequency is 'best' link.

4) Add per-link stats data that looks very much like 'sinfo' data struct and user-space
that can support that could then get detailed per-link stats at same time it is getting
per netdev 'sinfo' stats.

5) Assuming there will never be more than 3 links for any radios supported by Linux in the near future,
embed the 3 link's 'sinfo-like' stats data structure in the per-netdev sinfo stats struct
so that we can get all 3 link's data at same time that we are getting the other stats.
That should save calls into the driver and ensure that per-links stats can be gathered
at exactly the same time.

Thanks,
Ben


-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com