[Bloat] when does the CoDel part of fq_codel help in the real world?

[Pete Heist]

Thank you all for the responses!

I was asked a related question by my local WISP, who wanted to know if there would be any reason that fq_codel or Cake would be an improvement over sfq specifically for some "noisy links” (loose translation from Czech) in a backhaul that have some loss but also experience saturation. I conservatively answered no, but that may not be correct, in case the reduced TCP RTT could help with loss recovery or other behaviors, as Jon pointed out. I suspect more research would be needed to quantify this. Neal’s/Dave's point about “non-flow" traffic is well taken also.

> On Nov 26, 2018, at 11:13 PM, Toke Høiland-Jørgensen <toke at toke.dk> wrote:
> 
> Michael Welzl <michawe at ifi.uio.no> writes:
> 
>> However, I would like to point out that thesis defense conversations
>> are meant to be provocative, by design - when I said that CoDel
>> doesn’t usually help and long queues would be the right thing for all
>> applications, I certainly didn’t REALLY REALLY mean that.
> 
> Just as I don't REALLY REALLY mean that bigger buffers are always better
> as you so sneakily tricked me into blurting out ;)

I think most of us knew that “yeah” wasn’t a confirmation. Yeah can be used in a dozen different ways depending on context and intonation, but it did give some comic relief. :)

>> BTW, Anna Brunstrom was also very quick to also give me the HTTP/2.0
>> example in the break after the defense.
> 
> Yup, was thinking of HTTP/2 when I said "control data on the same
> connection as the payload". Can see from Pete's transcript that it
> didn't come across terribly clearly, though :P

Ah, sorry for missing that part! I thought there was more there but didn’t want to write something unless I was sure I heard it.

>> I’ll use the opportunity to tell folks that I was also pretty
>> impressed with Toke’s thesis as well as his performance at the
>> defense.

I’ll second that. I’m enjoying digesting the thesis, as well as the results of airtime fairness in a real world deployment. :)