[Codel] Exploring the potential of codel, fq_codel, and qfq

[Rick Jones]

On 05/16/2012 12:20 AM, Dave Taht wrote:
> After running those numbers I tried pure codel with ecn and with noecn
> just to verify results, against the 50 streams.
>
> of note: I was unable to duplicate the initial 120ms
> spike I saw. Definately more tests and more rigorous testing is needed.
>
> All tests were against v13 of the code.
>
> codel ecn off, you get an initial spike of about 30ms, then it settles
> down in this range.
>
> 64 bytes from 149.20.63.18: icmp_req=19 ttl=64 time=4.62 ms
> 64 bytes from 149.20.63.18: icmp_req=20 ttl=64 time=2.06 ms
> 64 bytes from 149.20.63.18: icmp_req=21 ttl=64 time=4.28 ms
> 64 bytes from 149.20.63.18: icmp_req=22 ttl=64 time=1.03 ms
> 64 bytes from 149.20.63.18: icmp_req=23 ttl=64 time=8.11 ms
> 64 bytes from 149.20.63.18: icmp_req=24 ttl=64 time=5.10 ms
>
> TCP_RR is: 112.69
>
> With ecn:
>
> 64 bytes from 149.20.63.18: icmp_req=46 ttl=64 time=10.6 ms
> 64 bytes from 149.20.63.18: icmp_req=47 ttl=64 time=5.66 ms
> 64 bytes from 149.20.63.18: icmp_req=48 ttl=64 time=11.8 ms
> 64 bytes from 149.20.63.18: icmp_req=49 ttl=64 time=3.68 ms
> 64 bytes from 149.20.63.18: icmp_req=50 ttl=64 time=10.2 ms
> 64 bytes from 149.20.63.18: icmp_req=51 ttl=64 time=12.8 ms
> 64 bytes from 149.20.63.18: icmp_req=52 ttl=64 time=2.62 ms
> 64 bytes from 149.20.63.18: icmp_req=53 ttl=64 time=7.86 ms
>
> TCP_RR: 102
>
> All of these sets of results need more rigor attached.

FWIW, netperf can report the number of retransmissions it saw on the 
data connection (when running on Linux).  That is enabled via the omni 
output selection and the local_transport_retrans and 
remote_transport_retrans output selectors.

rick jones