Re: ath10k fw_stats rx_frame/rx_clear counters

From: Ben Greear <greearb@candelatech.com>
To: Michal Kazior <michal.kazior@tieto.com>,
	Sergey Naumov <sknaumov@gmail.com>
Cc: "ath10k@lists.infradead.org" <ath10k@lists.infradead.org>
Subject: Re: ath10k fw_stats rx_frame/rx_clear counters
Date: Fri, 12 Jun 2015 06:43:50 -0700	[thread overview]
Message-ID: <557AE216.5020105@candelatech.com> (raw)
In-Reply-To: <CA+BoTQkjfiO-hZe+ngvRe0NCK=GroTMCeXuNNn9eb+BnRq+MJg@mail.gmail.com>

On 06/12/2015 12:16 AM, Michal Kazior wrote:
> On 11 June 2015 at 23:49, Sergey Naumov <sknaumov@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..

Here is a link to my previous email on the wrapping issue..it is not *just*
a matter of polling more often:

https://www.marc.info/?l=linux-wireless&m=143353920909147&w=2

After dealing with this, I see expected results when using 10.1.467 based
firmware (both CT and stock).

I am using WLE900VX NIC, my 4.0.4+ kernel.

Thanks,
Ben

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

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