[Rpm] Re: [Cake] Re: [Bloat] Re: CAKE-MQ merged to OpenWrt 25.12 today (February 15)

Stephen Hemminger
2026-02-17T14:34:17Z

On Tue, 17 Feb 2026 14:23:52 +0100
Toke Høiland-Jørgensen via Cake <cake@lists.bufferbloat.net> wrote:

> dave seddon <dave.seddon.ca@gmail.com> writes:
>
> > === Pre-flight Complete ===
> > Running 6 test points
> >
> > [1/6] qdisc=fq_codel flows=1 tool=iperf2
> > Switching qdisc to fq_codel...
> > Throughput: 9.41 Gbps
> > [2/6] qdisc=fq_codel flows=10 tool=iperf2
> > Throughput: 9.43 Gbps
> > [3/6] qdisc=cake flows=1 tool=iperf2
> > Switching qdisc to cake...
> > Throughput: 6.93 Gbps
> > [4/6] qdisc=cake flows=10 tool=iperf2
> > Throughput: 4.37 Gbps <---- cake
> > [5/6] qdisc=mq-cake flows=1 tool=iperf2
> > Switching qdisc to mq-cake...
> > Throughput: 7.17 Gbps
> > [6/6] qdisc=mq-cake flows=10 tool=iperf2
> > Throughput: 9.44 Gbps <-----
> > mq-cake ... Actually, that's interesting. higher than fq_codel
>
> Are you running fq_codel as the root qdisc? Because in that case you're
> running through the single qdisc lock, which could explain the
> difference. Try running separate fq_codel instances beneath an 'mq'
> qdisc as the root.
>
> Also, if you're not setting a shaping rate, cake_mq is basically the
> same as just installing an mq qdisc at the root and having separate cake
> instances beneath that. So to test the multi-core shaper algorithm
> you'll need to set a rate ('bandwidth' parameter).
>

This is what the OpenWrt SQM scripts seem to favor.
I probably need to tune the adaption overhead

# tc qdisc show dev wan
qdisc htb 1: root refcnt 2 r2q 10 default 0x12 direct_packets_stat 0 direct_qlen 1000
qdisc fq_codel 120: parent 1:12 limit 1001p flows 1024 quantum 300 target 5ms interval 100ms memory_limit 4Mb drop_batch 64
qdisc fq_codel 130: parent 1:13 limit 1001p flows 1024 quantum 300 target 5ms interval 100ms memory_limit 4Mb drop_batch 64
qdisc fq_codel 110: parent 1:11 limit 1001p flows 1024 quantum 300 target 5ms interval 100ms memory_limit 4Mb drop_batch 64

It is dumb that in US it is standard to offer 1G down and 10M up!