On 8/27/24 09:20, Johannes Berg wrote:
On Tue, 2024-08-27 at 09:12 -0700, Ben Greear wrote:
When be200 goes into eMLSR mode, both 5 and 6Ghz links are shown as active, so at least
you cannot use 'active link' to reliably update stats.
Sure, not active link - but there's an LMAC bit somewhere ... Ah, it's
not documented, it's actually documented *differently*, but it should be
bit 31 in len_n_flags in struct iwl_rx_packet.
Given the LMAC ID on the TX response notification we should know which
LMAC transmitted it, and then I think it's a simple mapping to the
active link. But I haven't actually really tried it.
If you can share a patch that documents this bit (like 0 means 5Ghz and 1 means 6Ghz??)
then we can try it out.
And maybe your idea for how to report it in tx-status too since that will touch
mac80211?
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...
I think first step is to get the driver(s) able to report the link-id in
the tx-status. After that, mac80211 can gather the stats.
Yeah, that makes sense, at least partially that's needed. I suspect that
also we need to extend the API down to the sta_statistics call though to
return per-link statistics, e.g. the TX bitrate would seem should be
reported per link, and that's done through that call now I believe.
Yes. At least at cfg80211 level, I think we should be able to query all
link stats in a single call into mac80211. Down in mac80211, then per-link
stats structs appears to be how things are done now and seems like a good
solution.
I hacked
tx/rx link stats into mac80211 ethtool (for first 3 links), but it is still not reliable since
mac80211 doesn't know the actual tx link id.
Right.
After that, then certainly I'd be happy to have per-link stats available,
and combining them in cfg80211 seems like a fine idea as well. Some things
that don't combine well (rssi, link rates, etc) would take a bit of kludging
if trying to provide a single 'sta' view of stats.
True, some can't just be added up and we'd have to find a sane different
"best" view, perhaps for rates it'd be the better of the two or the sum
if only reporting the bitrate, or better of the RSSI, etc. Case by case,
I guess.
I'd suggest using highest active band when we have no better option for
summing/combining.
Thanks,
Ben
--
Ben Greear <greearb@xxxxxxxxxxxxxxx>
Candela Technologies Inc http://www.candelatech.com
