From: Sven Eckelmann <sven.eckelmann@openmesh.com>
To: ath10k@lists.infradead.org
Cc: Anilkumar Kolli <akolli@codeaurora.org>,
        linux-wireless@vger.kernel.org, Antonio Quartulli <a@unstable.cc>,
        Felix Fietkau <nbd@nbd.name>,
        Marek Lindner <mareklindner@neomailbox.ch>,
        Johannes Berg <johannes.berg@intel.com>
Subject: Re: [PATCH v2] ath10k: Implement get_expected_throughput callback
Date: Mon, 26 Mar 2018 09:22:54 +0200
Message-ID: <2322769.sx4MhzsvNg@bentobox> (sfid-20180326_092305_775300_A4E0DC3F)
In-Reply-To: <1521814034-17880-1-git-send-email-akolli@codeaurora.org>
References: <1521814034-17880-1-git-send-email-akolli@codeaurora.org>
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On Freitag, 23. M=E4rz 2018 19:37:14 CEST Anilkumar Kolli wrote:
> +static u32 ath10k_get_expected_throughput(struct ieee80211_hw *hw,
> +                                         struct ieee80211_sta *sta)
> +{
> +       struct ath10k_sta *arsta =3D (struct ath10k_sta *)sta->drv_priv;
> +
> +       return ewma_sta_txrate_read(&arsta->ave_sta_txrate);
> +}

On Freitag, 23. M=E4rz 2018 19:11:48 CEST akolli@codeaurora.org wrote:
> > Antonio and Felix, please correct me when this statement is incorrect.
> >
> > The expected_throughput as initially implemented for minstrel(_ht) is=20
> > not
> > about the raw physical bitrate but about the throughput which is=20
> > expected for
> > things running on top of the wifi link. See
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/comm=
it/?id=3Dcca674d47e59665630f3005291b61bb883015fc5
> > for more details
> >
> > when I interpret your change correctly then your it doesn't get the
> > information about packet loss or aggregation and doesn't do anything=20
> > convert
> > from raw physical rate to something the user could get see. It will=20
> > just
> > overestimate the throughput for ath10k links and thus give wrong=20
> > information
> > to routing algorithms. This could for example cause them to prefer=20
> > links over
> > ath10k based hw when mt76 would actually provide a significant better
> > throughput.
> >
> > Beside that - why is the ave_sta_txrate only filled when with new=20
> > information
> > when someone requests the current expected_throughput via
> > get_expected_throughput. I would have expected that it is filled=20
> > everytime you
> > get new information about the current rate from the firmware
> > (ath10k_sta_statistics).
> >
> Yes. ideally it should be doing the rate avg. of all the sent packets.

No, not the PHY rate average - but the "throughput avg". And the "ideally"=
=20
here sounds a little bit like in "Our medical doctor would ideally not=20
decapitate each patient but we have at least an MD".

Kind regards,
	Sven
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