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

[Marek Lindner <mareklindner@neomailbox.ch>]

[-- 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 --]