Re: About Throughput in BATMAN_V

[Marek Lindner <mareklindner@neomailbox.ch>]

Hi,

> We have two modems for each node and in one of them, expected throughput
> should be about 6 Mb/s for example, and in the other one it should be about
> 30 Mb/s. By using iperf and also throughput meter I can see that it's the
> case. But when they are added to batman with batctl if add, after typing
> batctl o, I see that the throughput values in both interfaces are 10000
> instead.
> 
> I looked at the interfaces with ethtool and the speed is 10000 Mb/s there
> for both too which is how batman must be measuring the throughput

correct. If the underlying interface provides a link speed via ethtool, batman 
uses the ethtool API to get the throughput value.


> If we use throughput override, it's fine at first but one of the modems has a
> shorter range so in our test where two nodes move away from each other,
> actual throughput gets decreased due to losses but batman still chooses the
> same interface due to the overriden value.

That is what the manual override is meant to do. A manual value that will 
override all dynamically determined values.

Can you explain what type if "modem" you are talking about? It is not clear 
why a modem depends on range. Or are you talking about a batman mesh 
connecting various modems? Please share the topology of your setup.

Is this somehow related to your earlier statement: "[..] but then even when 
actual throughput of the active interface decreases, it doesn't switch to the 
other interface because it only considers the overriden value." ?


> Basically I would prefer batman being able to change measured throughput
> dynamically.

if I understand correctly you are changing from "Batman doesn't seem to 
calculate throughput properly" to "measured throughput is preferable" ? There 
is no calculation issue with batman v?

Cheers,
Marek