ath10k fw_stats rx_frame/rx_clear counters

[Michal Kazior]

On 11 June 2015 at 23:49, Sergey Naumov <sknaumov at gmail.com> wrote:
> Hi all.
>
> I'm using barrier breaker OpenWRT on TP-link Archer C7 v2.0 router and
> looking at /sys/kernel/debug/ieee80211/phy0/ath10k/fw_stats content.
> As far as I understand "RX frame" accounts just rx of our and all the
> other APs on the same channel, while "RX clear" also accounts tx of
> our AP and non-wifi interference.
> At least it is true for ath9k with 2.4GHz chip on the same router,
> where "channel busy time" from survey report is always greater than
> "channel receive time".
>
> But for ath10k I see that with absense of the traffic to/from our AP,
> "RX frame" register value is always increased a little bit more than a
> value of "RX clear" register, and it is strange.
>
> Do you know what could be a reason?

What is the interval you're polling the values at? There's a buggy 24
second wraparound on these cycle count related stats. Maybe you're
hitting that..

Another idea/guess is that firmware doesn't read these values
atomically (I recall ath9k locks CC values via control register before
reading them) and it ends up with inconsistent results.


> P.S. I tried new Chaos Calmer RC1 OpenWRT release with updated ath10k
> driver and binary firmware and there these low-level stats are
> unavaiable (file /sys/kernel/debug/ieee80211/phy0/ath10k/fw_stats
> exists but read returns error).

The firmware stats interface has a very clunky and unstable ABI. It's
broken often by firmware updates and remains so until someone
notices..

Can you provide more details, please:
 - which revision of CC you're using,
 - what ath10k firmware version is used,
 - what compat package version ath10k is from.


Michał