Re: [Make-wifi-fast] [PATCH] mac80211: Dynamically set CoDel parameters per station.

[Loganaden Velvindron <loganaden@gmail.com>]

On Sat, Sep 10, 2016 at 11:54 PM, Jim Gettys <jg@freedesktop.org> wrote:
>
>
> On Sat, Sep 10, 2016 at 3:33 PM, Toke Høiland-Jørgensen <toke@toke.dk>
> wrote:
>>
>> CoDel can be too aggressive if a station sends at a very low rate,
>> leading to starvation. This gets worse the more stations are present, as
>> each station gets more bursty the longer the round-robin scheduling
>> between stations takes.
>>
>> This adds dynamic adjustment of CoDel parameters per station. It uses
>> the rate selection information to estimate throughput and sets more
>> lenient CoDel parameters if the estimated throughput is below a
>> threshold. To not change parameters too often, a hysteresis of two
>> seconds is added.
>
>
> Where is this 2 second constant coming from?  I'd expect it should be of
> order the maximum RTT (or a small constant factor of that, which for
> intercontinental connections should be 200-300ms.
>

Indeed, from Mauritius (Africa) to remote countries like Australia, or
parts of the US, we see latencies of up to 500-600ms.