Re: [PATCH] batman-adv: Use wifi rx/tx as fallback throughput

Marek Lindner
2019-06-10T03:31:48Z

[-- Attachment #1: Type: text/plain, Size: 2476 bytes --]

On Sunday, 9 June 2019 20:45:06 HKT René Treffer wrote:
> I am testing this on devices with ath9k (2.4GHz) and ath10k (5GHz), so I
> was looking at the estimates I get from ath9k. Here is a dump from my
>
> home network on 2.4GHz/ath9k and what rx/3 would give us:
> > signal tx rx expect tx/3 min(tx/3,(rx+tx)/2/3)
> > -77 13.0 43.3 6.682 4.333
> > -57 130.0 117.0 44.677 43.333 41.166
> > -53 117.0 130.0 42.388 39.0
> > -82 43.3 6.5 13.366 14.433 8.3 (!!!)
> > -63 52.0 86.7 26.733 17.333
> > -58 130.0 173.3 29.21 43.333 !!!
> > -82 6.5 43.3 2.197 2.166
> > -48 104.0 65.0 40.191 34.666 28.166
> > -69 57.8 13.0 20.49 19.266 11.8
> > -58 86.7 52.0 33.507 28.9 23.116
> > -58 52.0 1.0 37.994 17.333 8.833
> > -56 115.6 144.4 29.21 38.533 !!!

To confirm my understanding: What this table shows are raw tx/rx link estimated
values ? None of these numbers compares to Minstrel HT expected throughput or
actual throughput ?

> Cases where the rx/tx estimate would be higher are marked with !!!.

I also don't quite understand what the '!!!' thing is trying to indicate. What
is being compared ? But it may be due to my misunderstandings above.

In my small test setup with one ath10k device meshing with ath9k over 2.4GHz,
your tx / 3 formula seems to be quite accurate (had removed the rx part).

# batctl o (your magic formula)
* ac:86:74:00:38:06 0.930s ( 45.7) ac:86:74:00:38:06 [ mesh24]

# batctl tp ac:86:74:00:38:06 (actual throughput)
Test duration 10440ms.
Sent 58393512 Bytes.
Throughput: 5.33 MB/s (44.75 Mbps)

What would be interesting is how the numbers produced by 'tx / 3' compare to
either the actual throughput (can easily be tested with the throughput meter)
or Minstrel expected throughput.

> Why bother and look at rx at all? Asymmetric routing should already
> work. I was bit concerned about highly asymmetric links, especially
> those where the path back might not work. It might not be worth it though.

Generally, the return path might be entirely different. Batman-adv does not
enforce or even endorse symetric paths. If there is better path for the return
route, batman-adv will choose the better path based on tx from the sender and
if only one return path exists, we don't care anyway ..

Cheers,
Marek

[-- Attachment #2: This is a digitally signed message part. --]
[-- Type: application/pgp-signature, Size: 488 bytes --]