[Cake] Munin-Plugins
Jonathan Morton
chromatix99 at gmail.com
Wed Sep 19 22:13:03 EDT 2018
> On 20 Sep, 2018, at 4:39 am, Ruben <ruben at vfn-nrw.de> wrote:
>
> > There's no counter for ecn marked packets in bytes, so it's impossible to
> > implement it that way, too.
> >
> > ECN-Marks is in packets, so everything else need to be in packets as
> > well.
>
> Hmm, so the obvious follow-up question would be "why do you need to have
> backlog and number of drops on the same graph?" :)
>
> I think the answer is obvious: The graph has the purpose to show the pressure on the qdisc, so backlog is a reasonable number to show, even if combining backlog with drops is a far fetch from data science standpoint.
I don't see any real conflict between measuring backlog in bytes and marking events in discrete packets per second. You need to provide a dual axis scale to fit them on the same graph, that's all - but you'd probably need to do that anyway, because the units of measurement would still be different.
More generally, I have accepted the Codel premise that time is more important for congestion control than either bytes or packets; for a wired link, bytes are closer to a measure of time than packets are (because packets of different sizes can have wildly different serialisation delays and line occupancy). For wifi, aggregation patterns have a bigger effect on time measures than the raw number of bytes involved.
There *is* a readout of total backlog packets as well as bytes, just not one per tin.
- Jonathan Morton
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