[Bloat] The NetEm qdisc does not work in conjunction with other qdiscs

[Dave Taht]

What I would typically do is setup netem on an inbound qdisc and whatever
is under test on the outbound.

even then, care is needed to ensure netem itself is not the bottleneck, has
an appropriate packet limit (I use millions), and that you are not running
out of cpu. For example it is really hard to pull 4gbit on cheap hw with
default qdiscs.

On Fri, Oct 25, 2024 at 11:54 AM Joerg Deutschmann via Bloat <
bloat at lists.bufferbloat.net> wrote:

> Dear all,
>
> bringing up again the question from a previous message to this list...
>
>
> https://www.bufferbloat.net/projects/codel/wiki/Best_practices_for_benchmarking_Codel_and_FQ_Codel/#the-netem-qdisc-does-not-work-in-conjunction-with-other-qdiscs
> says to not use NetEm together with other qdiscs.
>
> Is this still true?
>
> How could one emulate bottlenecks together with fq_codel?
>
> Best regards
> Joerg
>
>
> On 15.01.24 13:24, O. P. via Bloat wrote:
> >
> > Hi there,
> >
> > I'm trying to set up a testbed to evaluate different AQM techniques
> > using docker containers.
> > My first idea to create congestion was to use netem. However I later
> > came across
> >
> https://www.bufferbloat.net/projects/codel/wiki/Best_practices_for_benchmarking_Codel_and_FQ_Codel/
> <
> https://www.bufferbloat.net/projects/codel/wiki/Best_practices_for_benchmarking_Codel_and_FQ_Codel/>
> which discourages using netem. Since the document is from 2014 and also
> states that "netem has been improving", my question was wether the current
> netem has improved sufficiently to be used to get realistic results.
> > If netem has improved sufficienly, what would be the correct way to use
> > netem along fq, fq-codel or codel for example ?
> > If not, is HTB still the best way to perform rate limiting ? Is there a
> > prefered way to combine HTB with AQMs ?
> >
> > Best regards
> >
> > John
> >
> > _______________________________________________
> > Bloat mailing list
> > Bloat at lists.bufferbloat.net
> > https://lists.bufferbloat.net/listinfo/bloat
> _______________________________________________
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>


-- 
Dave Täht CSO, LibreQos
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