netdev - Re: [PATCH] ath9k: add reset for airtime station debugfs

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Date:   Sun, 9 Sep 2018 16:44:53 -0700
From:   Dave Taht <dave.taht@...il.com>
To:     Toke Høiland-Jørgensen <toke@...e.dk>
Cc:     git@...ie.lu, Kalle Valo <kvalo@...eaurora.org>,
        QCA ath9k Development <ath9k-devel@....qualcomm.com>,
        "David S. Miller" <davem@...emloft.net>,
        linux-wireless <linux-wireless@...r.kernel.org>,
        Linux Kernel Network Developers <netdev@...r.kernel.org>
Subject: Re: [PATCH] ath9k: add reset for airtime station debugfs

On Thu, Sep 6, 2018 at 4:13 AM Toke Høiland-Jørgensen <toke@...e.dk> wrote:
>
> Louie Lu <git@...ie.lu> writes:
>
> > Toke Høiland-Jørgensen <toke@...e.dk> 於 2018年9月6日 週四 下午5:27寫道：
> >
> >> Louie Lu <git@...ie.lu> writes:
> >>
> >> > Let user can reset station airtime status by debugfs, it will
> >> > reset all airtime deficit to ATH_AIRTIME_QUANTUM and reset rx/tx
> >> > airtime accumulate to 0.
> >>
> >> No objections to the patch, but I'm curious which issues you were
> >> debugging that led you to needing it? :)
> >>
> > I'm testing to get the packet queue time + airtime in
> > ath_tx_process_buffer,
>
> Right; I've been thinking that it would be useful to make the CoDel
> enqueue time available to drivers. And minstrel, for that matter
> (lowering the number of retries for packets that has queued for a long
> time, for instance). Good to hear that others are looking into something
> similar :)

Yea! Seeing retransmits scale down would be a goodness. Last I looked
ath9k was at, like 10?, when it should be, like, 2, at mcs0 and 10 at
mcs15.

I can't seem to publish a link to this directly, but it's open access
if you search via https://scholar.google.com/:

"Resolving Bufferbloat in TCP Communication over IEEE 802.11 n WLAN by
Reducing MAC Retransmission Limit at Low Data Rate"

even their simple bifurcated model worked well.




>
> > it would be useful if I can reset the station airtime accumulated
> > value, so I can observe in each test round (e.g. 5 ping) airtime
> > accumulated
> >
> > Also to reset the deficit to make sure it run like fresh one.
>
> Yup, makes sense.
>
> -Toke



-- 

Dave Täht
CEO, TekLibre, LLC
http://www.teklibre.com
Tel: 1-669-226-2619