On Tue, 2024-08-27 at 09:28 -0700, Ben Greear wrote: > 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. I think yes, 5 GHz should be on LMAC 0 and 6 GHz on LMAC 1, and that's the only case where we can have two active links simultaneously. There's still a race though, when we change the active links while transmitting, not sure how to handle that. Oh wait, it's simpler than that - we have the STA pointer in there already (see iwl_mvm_rx_tx_cmd_single and iwl_mvm_rx_tx_cmd_agg), but since we get that from the FW STA ID, we obviously also know the *link* STA since the FW STA IDs are per link, so we can just go from there to the link ID directly. link_sta = rcu_dereference(mvm->fw_id_to_link_sta[notif->sta_id]); link_sta->link_id > And maybe your idea for how to report it in tx-status too since that will touch > mac80211? I hadn't really thought about that ... I guess we could use the IEEE80211_TX_CTRL_MLO_LINK space also for status? It's already filled to the link ID by mac80211 for TX if the frame must go out on a specific link (or 0xF otherwise which is an invalid link ID anyway.) > > > > > 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. Not sure I have a strong opinion on this being a single call or not, either way seems reasonable really. > > > > > 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. But is that the most useful thing? What if the RSSI is quite bad there (but still good) and then NetworkManager shows a really weak signal when in reality you have a good connection on another link? Anyway, dunno, we're not near that bridge yet I think ;) johannes
