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From:   Kalle Valo <kvalo@kernel.org>
To:     Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Cc:     Edmond Gagnon <egagnon@squareup.com>,
        Benjamin Li <benl@squareup.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>, wcn36xx@lists.infradead.org,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/2] wcn36xx: Implement tx_rate reporting
In-Reply-To: <cda7eaa6-fb99-0d32-24fb-758b9363ee6d@linaro.org> (Bryan
        O'Donoghue's message of "Sun, 20 Mar 2022 18:03:10 +0000")
References: <20220318195804.4169686-1-egagnon@squareup.com>
        <20220318195804.4169686-3-egagnon@squareup.com>
        <c8f31312-5356-704e-1f55-89c9f5888238@linaro.org>
        <cda7eaa6-fb99-0d32-24fb-758b9363ee6d@linaro.org>
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Date:   Sun, 20 Mar 2022 21:15:25 +0200
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Bryan O'Donoghue <bryan.odonoghue@linaro.org> writes:

> On 20/03/2022 13:21, Bryan O'Donoghue wrote:
>> On 18/03/2022 19:58, Edmond Gagnon wrote:
>>> +=C2=A0=C2=A0=C2=A0 INIT_DELAYED_WORK(&wcn->get_stats_work, wcn36xx_get=
_stats_work);
>>
>> Instead of forking a worker and polling we could add the relevant
>> SMD command to
>>
>> static int wcn36xx_smd_tx_compl_ind(struct wcn36xx *wcn, void *buf,
>> size_t len)
>> {
>>  =C2=A0=C2=A0=C2=A0 wcn36xx_smd_get_stats(wcn, 0xSomeMask);
>> }
>>
>> That way we only ever ask for and report a new TX data rate when we
>> know a TX event - and hence a potential TX data-rate update - has
>> taken place.
>>
>> ---
>> bod
>>
>
> Thinking a bit more
>
> - Do the SMD get_stats in the tx completion
>   This might be a problem initiating another SMD transaction inside
>   of an SMD callback. But is the most straight forward way to
>   get the data while avoiding alot of needless polling.
>
> - Schedule your worker from the TX completion
>   Again you should only care about gathering the data when you know
>   something has happened which necessitates gathering that data
>   like TX completion
>
> - Schedule your worker from the RX indication routine
>   Seems not as logical as the first two but it might be easier
>   to schedule the worker in the RX data handler
>
> Either way, I do think you should only gather this data on an event,
> not as a continuous poll.

I agree, a continuous poll is not a good idea as it affects power
consumption. What about struct ieee80211_ops::sta_statistics? AFAIK
that's called only when user space is requestings stats so the overhead
should be minimal.

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