Re: Per MLO link TX stats

[Johannes Berg <johannes@sipsolutions.net>]

On Fri, 2024-07-12 at 10:52 -0700, Ben Greear wrote:
> Hello,
> 
> I've been trying to get better per MLO link stats.  I see that the rx path
> stats are there, but in the tx path, I do not see anything other than 'deflink'
> getting updated.

Yeah, nobody really cared too much about statistics yet. I know. Sorry.
Not much time to work on it either now.

> And, at least with iwlwifi, I cannot find any way to actually see what link-id
> was used to transmit a frame in the tx status callbacks (or anywhere else I looked).

You can probably derive that from the band for iwlwifi, since it only
supports one active link on each 2.4 / 5 / 6 GHz if at all. And the band
I guess you'd get from the LMAC ID or something. Should be in there
somewhere... IOW, I think it's possible, but I'm also not entirely sure
how we'd do it.

> In the case where there is a single active link, then I can hack something together
> that should be at least mostly right, but that won't fix any future radio that can
> do 2+ active links.
> 
> Any suggestions for best path forward on this?

I really think we also need to do some work on the API/cfg80211 level,
and have link station statistics in cfg80211 instead of full station,
and then combine them to (older) userspace in cfg80211, i.e. if
userspace doesn't request broken out per-link statistics. There's
probably a bunch of work here, and I only have a vague idea of how it
should be done...