On 28.08.19 19:34, Joe Ayers wrote:
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.
Will try to verify this one
* 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.
Ack on this one.
Tested on links ranging from ~500m up to 3.5km
static seems to win in terms of performance until the distance goes
beyond ~6km here
There seems to be something going on with calculation when 'on the
bench' testing with short distances. Maybe a bias needs to be
applied?
I notice that ack_to never drops below 64 on short distance links.
(static sets it to 31 on selecting 500m)
I wonder if processing delay/time and thread context switching is coming
into play here on the slower ar71xx socs
Will check it.
The main focus of this series was to have working links and avoid
breaking existing ones.
I think the next round will be regarding these performance "issues"
compared to static
Koen
Joe AE6XE
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