I completely neglected this. It turns out sometimes netem drops, sometimes it doesn't.
This would also explain the different behaviour I am getting (rrul1) sometimes.
I guess it is because netem doesn't drop in this case. 

I am attaching a new file with both cases (I could replicate them again).
Delay's netem and mbox's cake stats are in the txt files.

Is a limit of 4000 a sane value?
Calculated as (0.05s * 900mbit/s / 8bit/byte / 1500bytes/packet)??

George

On Wed, Nov 29, 2017 at 1:00 PM, Dave Taht <dave@taht.net> wrote:
Georgios Amanakis <gamanakis@gmail.com> writes:

> ---------- Forwarded message ----------
> From: Georgios Amanakis <gamanakis@gmail.com>
> Date: Wed, Nov 29, 2017 at 12:50 PM
> Subject: Re: [Cake] cake flenter results round 2
> To: Dave Taht <dave@taht.net>
>
> To avoid a misunderstanding, the delay parameter in both:
> "ip netns exec delay tc qdisc replace dev delay.r root netem delay 50ms"
> "ip netns exec delay tc qdisc replace dev delay.l root netem delay 50ms"

I would strongly suspect you are seeing drops in these qdiscs also
without the increased limit, at the increased delay, at 900mbit (go
check with ip netns exec delay tc -s qdisc show)

My original scripts were targeted at 16Mbit/1mbit and thus I didn't
change the limit.