Re: [PATCH RFC] batman-adv: BATMAN V: use/prefer 11s airtime link metric

[Marek Lindner <marek.lindner@mailbox.org>]

On Saturday, 18 January 2025 01:35:27 CET Linus Lüssing wrote:
> When no expected throughput is available then HWMP keeps track of the
> average packet delivery error rate and average phy rate to calculate its
> own expected throughput value.

Is this also the case when 11s mesh forwarding is disabled?


> So the 11s airtime link metric should be a slightly better estimate than
> the expected throughput provided by Minstrel. And should be significantly
> better than our raw PHY rate divided by 3 guestimate fallback.

Have you tested the airtime metric in real world setups or what leads you to 
conclude that 11s airtime link metric is better than expected throughput?

Generally speaking, I like the idea of adding another link metric source.


> +static u32 batadv_v_elp_get_throughput_from_11s(u32 airtime)
> +{
> +       const int tu_to_airtime_unit = 100;
> +       const int test_frame_len = 8192;
> +       const int tu_to_us = 1024;
>
> +       return test_frame_len * 100 * tu_to_airtime_unit / (airtime * 
tu_to_us);

Are these values constant across all platforms and drivers?

Maybe there should be a function call to an 11s function doing the conversion 
and handling all cases (instead of doing this in the batman-adv code)?


>         struct station_info sinfo;
>  -       u32 throughput;
> +       u32 throughput, airtime;

The Reverse Christmas Tree style should be accounted for.

Cheers,
Marek