[Bloat] "BBR" TCP patches submitted to linux kernel

[Dave Taht]

On Thu, Oct 27, 2016 at 10:04 AM, Steinar H. Gunderson
<sgunderson at bigfoot.com> wrote:
> On Fri, Oct 21, 2016 at 10:47:26AM +0200, Steinar H. Gunderson wrote:
>> As a random data point, I tried a single flow from my main server in .no
>> to my backup server in .nl and compared CUBIC (with sch_fq) to BBR (naturally
>> also in sch_fq) on the sender side. The results were quite consistent across
>> runs:
>
> Another datapoint: A friend of mine had a different, worse path (of about 40 ms)
> and tested with iperf.
>
> CUBIC delivered 20.1 Mbit/sec (highly varying). BBR delivered 485 Mbit/sec.

I mostly live in a world (wifi) where loss is uncommon, unless forced
on it with a AQM.

At the moment my biggest beef with BBR is that it ignores ECN entirely
(and yet negotiates it). BBR is then so efficient at using up all the
pipe that a single queued aqm "marks madly" and everything else
eventually starves. Watch "ping" fade out here...

http://blog.cerowrt.org/flent/bbr-comprehensive/bbr_ecn_eventually_starving_ping.png

somewhat conversely in fq_codel, this means that it ignores codel's
marking attempts entirely and BBR retains it's own dynamics, (while
the non-BBR flows are fine) which is kind of neat to watch.

> /* Steinar */
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> Homepage: https://www.sesse.net/
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-- 
Dave Täht
Let's go make home routers and wifi faster! With better software!
http://blog.cerowrt.org