[Codel] fq_"codel" in apple's gear

[Dave Taht]

I would be curious if fq_"codel" was still in use on the current apple
products. On an OSX box, the magic command to look at the stats was:

netstat -I en0 -qq # or whatever the right interface is

And you can just poll that while slamming traffic through it.

On Sat, Oct 14, 2023 at 11:50 AM Dave Taht <dave.taht at gmail.com> wrote:
>
> On Sat, Oct 14, 2023 at 11:17 AM Jonathan Morton <chromatix99 at gmail.com> wrote:
> >
> > > On 14 Oct, 2023, at 8:23 pm, Dave Taht <dave.taht at gmail.com> wrote:
> > >
> > > I would really like someone with a fresh set of eyeballs to review the
> > > "codel"  portion of apple's latest code drop here:
> > >
> > > https://www.linkedin.com/feed/update/urn:li:activity:7118969694987935744/
> >
> > So far as I can tell, it still implements DRR++ (with a comment referencing RFC-8290), but not Codel (there's also no comment referencing RFC-8289).  There's at least one function for handling ECN which is simply not called, at least not in that source file.
>
> Thank you for summoning the gumption to look again. I was having blood
> pressure problems.
>
> > In fact, I looked in the header to see where an ECN mark counter was defined.  It is referenced in essentially three places:  the definition, an extraction for reporting to userspace, and an increment - in a function implementing L4S marking, not Codel.
> >
> > A similar counter for "early dropped" packets is incremented only when packets have to be dropped in an emergency because the queue is *full*.  That's the other counter I would expect to be touched by an AQM implementation.
>
> Yep. I had run some tests then and saw the rtts climbing alarmingly,
> while polling their stack and only seeing drops in big bursty batches,
> total resets of the tcp flow, and so on.
>
> > So, no tangible improvement that I can find easily.
> >
> >  - Jonathan Morton
>
>
>
> --
> Oct 30: https://netdevconf.info/0x17/news/the-maestro-and-the-music-bof.html
> Dave Täht CSO, LibreQos



-- 
Oct 30: https://netdevconf.info/0x17/news/the-maestro-and-the-music-bof.html
Dave Täht CSO, LibreQos