[OpenWrt-Devel] ath9k: fix dynack in IBSS mode

[Joe Ayers]

> > initialized the ackto to max:
> >
> > A) avoidance of late-ack state
> > B) not require wpa_supplicant  -- not in use by our community today
> > C) Suspect some conditions, e.g. low SNR Neighbors, do not trigger
> > "late ack" (consistent, with observation of low SNR Neighbors sticking
> > at max ack_to with my changes )
> >
> > flip the algo off/on when new neighbor joins:
> >
> > Intended technique to reset ack_to to max.  If ack_to is set to 20km
> > and then a new adhoc neighbor joins at 30km, this would be a late ack
> > state, and unable to detect.    My early testing results showed the
> > algo off/on would restart the ack_to to max and start the process over
> > with the new neighbor.   I trust I got it right?
> >
> > There are 10s to 100s of users testing this bleeding edge change from
> > nightly builds, and so far, I've not found a failure case.
> > Although, the findings are showing the cases where static setting has
> > better throughput.
> >
> > Joe AE6XE
> >
> >>>
> Hi Joe,
>
> Purely fyi
>
> I just pushed dynack improvements to all openwrt branches.
>
> I also noticed the issues you addressed above, and these patches fix
> them for me.
>
> Regards,
>
> Koen
>

Thanks for update.   Updates on performance observations, I've been
recommending usage of auto settings to the AREDN community as follows:

* best performance gain on Point-to-Point longer distance links (back
bone links).  I saw ~30% iperf improvement results on a 60km 5GHz link
-- ack-to floats up under load.   This was about the difference I
measured on a similar 3GHz  60km link head-to-head comparison between
AirOS auto distance with TDMA and openwrt static distance with CSMA.
(3GHz because it takes wifi noise out of the picture.)  I want to do a
head-to-head comparison again to confirm, but it appears a P2P w/ auto
setting CSMA in openwrt will compare similar thoughput as AirOS auto
distance TDMA.
* good/poor performance for Point-to-Multipoint long distance
settings, up to 20km  range (cell coverage).   If weak SNR stations, a
static setting is optimal.  If quality signal, auto works good.
* Poor performance for short distances, e.g. in the house.   auto
calculated ack_to settings are several km.  Performance is much poorer
than a static setting of <1km.

There seems to be something going on with calculation when 'on the
bench' testing with short distances.   Maybe a bias needs to be
applied?

Joe AE6XE

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