[Cake] a little bit of cake testing

Jonathan Morton chromatix99 at gmail.com
Thu Jun 4 16:31:44 EDT 2015


In summary, the new Codel behaviour works better on egress but worse on
ingress. That's reasonable - on ingress the queue always appears to build
slowly, so the new scheme always triggers late, and is more likely to
return aggressively to a lower signalling rate. I think we're going to need
a special mode for ingress.

However, I think a good deal of your poor results are due to not properly
matching the actual link bandwidth any more. I would suspect trouble in the
cable rather than the modem, given the symptoms.

- Jonathan Morton
 On 4 Jun 2015 21:11, "Dave Taht" <dave.taht at gmail.com> wrote:

> not very well controlled dataset at:
> http://snapon.lab.bufferbloat.net/~d/fishcake/
>
> On Thu, Jun 4, 2015 at 11:10 AM, Dave Taht <dave.taht at gmail.com> wrote:
> > I did a bit of setup on my connection to give me a decent rrul result.
> > (I was not rate limiting inbound enough) The duration of the initial
> > load spike is much less pronounced than the fq_codel result. I note
> > that I have offloads still on, so I imagine fq_codel is getting
> > tweaked by that....
> >
> > but ingress gets way out of hand later on in this test. I can make an
> > argument for decay (count/2) being far too aggressive. In fact, even
> > count - 2 seemed too much in older testing I had done with other
> > variants. I would certainly like to get a feel for when and where the
> > three parts of codel are kicking in in various workloads.
> >
> > http://www.dslreports.com/speedtest/613646
> >
> > I really need to get to where I can quickly get to a blog entry on
> > this stuff, and back to comprehensive, controlled testing.
> >
> >
> >
> >
> >
> > On Thu, Jun 4, 2015 at 10:11 AM, Dave Taht <dave.taht at gmail.com> wrote:
> >> My network here is in flux (new modem, signal strength problems, cable
> >> problems) and toke's testbed is presently doing wifi work, so I did a
> >> quick mod to fishcake to make it do linux 4.0 (note I am not sure if
> >> this was a 4.1 or a 4.0 change) - attached. (and we lose a few cake
> >> options due to me not grokking the new API)
> >>
> >> Cake did well on this, but the behavior at the tail end of the test
> >> was disturbing:
> >>
> >> http://www.dslreports.com/speedtest/611312
> >>
> >> Need to do some work to emulate the dslreports tests.
> >>
> >> And it dropped  LOT more packets than fq_codel did. fq_codel marked 33
> >> packets for it's result, cake marked 600 and dropped 200, for its.
> >>
> >> I did some rrul testing as well, but was fighting with a modem that
> >> used to get 140Mbits, and now only gets 70mbits, and behaves very
> >> differently overall with pfifo_fast than i had ever seen before. And
> >> along the way snapon got upgraded a bit too... sigh...
> >>
> >> --
> >> Dave Täht
> >> What will it take to vastly improve wifi for everyone?
> >> https://plus.google.com/u/0/explore/makewififast
> >
> >
> >
> > --
> > Dave Täht
> > What will it take to vastly improve wifi for everyone?
> > https://plus.google.com/u/0/explore/makewififast
>
>
>
> --
> Dave Täht
> What will it take to vastly improve wifi for everyone?
> https://plus.google.com/u/0/explore/makewififast
> _______________________________________________
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> Cake at lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/cake
>
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