[Cerowrt-devel] [Cake] apu2 sqm/htb issue + a minor win for speeding up fq_codel itself

Mikael Abrahamsson swmike at swm.pp.se
Fri Oct 5 08:52:41 EDT 2018

On Wed, 3 Oct 2018, Mikael Abrahamsson wrote:

> On Wed, 3 Oct 2018, Dave Taht wrote:
>> I *think*, but am not sure, this box could do a lot more prior to
>> this, but I never really tried. I'm off mostly debugging a babel
>> problem at the moment,
> I know for a fact that this box (WRT1200AC) did gigabit at MSS=400 one-way 
> using fq_codel/cake before. I tested it a lot back then. Right now, I am 
> using it as a 250/100 megabit/s machine, and it seems to spend a lot CPU 
> doing that.

I did some new tests. Now I can't reproduce the problem.

I installed 18.06.1 and it'll do single TCP flow MSS 200 (-M 200 in 
iperf3) at 550 megabit/s shown in iperf3, and 87% sirq shown in top on 
WRT1200AC. When I set in/out speed at 800M and enable cake/layer_cake.qos 
then performance drops to ~400 megabit/s with the same packet flow. So the 
performance degradation is only around 20%, which I think is perfectly 
acceptable. I get very similar results with fq_codel and simple.qos.

I also took some power meter readings, WRT1200AC idles as 9.2W and at full 
CPU goes up to 10.4W.

Mikael Abrahamsson    email: swmike at swm.pp.se

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