[Codel] what am i doing wrong? why isn't codel working?

[Eric Dumazet]

On Tue, 2014-06-24 at 09:22 -0400, Brian J. Murrell wrote:
> Hi all,
> 
> I've upgraded my router to OpenWRT Breaker Barrier r41163 which has
> kernel 3.10.36 in it.  I was pleased to see that codel appears (to my
> very newbie eyes) to be default on what should be the
> "fast->slow" (where bufferbloat happens) interfaces:
> 
> qdisc fq_codel 0: dev eth0 root refcnt 2 limit 1024p flows 1024 quantum 300 target 5.0ms interval 100.0ms ecn 
> qdisc mq 0: dev wlan1 root 
> qdisc mq 0: dev wlan0 root 
> qdisc fq_codel 0: dev pppoe-wan1 root refcnt 2 limit 1024p flows 1024 quantum 300 target 5.0ms interval 100.0ms ecn 
> qdisc fq_codel 0: dev tun0 root refcnt 2 limit 1024p flows 1024 quantum 300 target 5.0ms interval 100.0ms ecn 
> 
> So first thing to notice is that this router has two WAN interfaces but
> only one of them (pppoe-wan1) has had codel applied.  The other WAN
> interface (eth0.2) is not even listed.
> 
> So off I go to experiment with the WAN interface that does have codel
> applied...
> 
> So I do the saturate-and-ping test through pppoe-wan1 and ping times go
> from ~12ms to ~1200ms, while saturating the upstream so clearly codel is
> not working there.
> 
> What am I doing wrong?


Maybe queue builds after the qdisc.

ethtool eth0
ethtool -g eth0