Re: [Cerowrt-devel] fq_pie for linux

[Dave Taht <dave.taht@gmail.com>]

On Tue, Dec 11, 2018 at 12:23 PM Toke Høiland-Jørgensen <toke@toke.dk> wrote:
>
> Jonathan Morton <chromatix99@gmail.com> writes:
>
> >> On 11 Dec, 2018, at 8:32 pm, Aaron Wood <woody77@gmail.com> wrote:
> >>
> >> With all the variants of fq+AQM, maybe decoupling the FQ part and the
> >> AQM part would be worthwhile, instead of reimplementing it for each
> >> variant...
> >>
> >> That's a great idea, Toke.  There are a lot of places where I think it could work well, especially if it took a pluggable hash function for the hashing (at which point it's very general-purpose, and works on all sorts of different kinds of packets and workloads).  That would let it be used for userspace VPN links (as an example), or within QUIC (or similar), where the kernel can't see the embedded flows that are hidden by the TLS encryption.
> >>
> >> And having it pluggable in the kernel would also allow IPSec to work
> >> without bloat (last I checked it was horribly bufferbloated, but that
> >> was ~5 years ago).
> >
> > I wonder if it's worth extracting the triple-isolate and
> > set-associative hash logic from Cake for this purpose?  The interface
> > to COBALT is clean enough to be replaced by other AQMs relatively
> > easily.
>
> There's already a reusable FQ structure in the kernel (which is what the
> WiFi stack uses), which is partially modelled on Cake's tins. I had half
> a mind to try to have the two converge; Cake would shed some LOCs, and
> the WiFi stack could get set-associativity...

I'm totally not sold on the need for set-associativity. Recently
though, I started thinking about doing dynamic minimal perfect
hashing, as most ip addresses (and for that matter, mac addresses) are
pretty long term stable. If we can calculate a minimal perfect hash
(see cmph for example) fairly rapidly set associativity goes away...
(but I don't have huge hopes for it as yet)

I'm also impressed with the early analysis of cobalt's AQM implementation.

I would like very much, however, for a close look at how much
ack-filtering would benefit wifi.

and funding for next year is on my mind. Not sure how to wedge
anything into nl.net's RFP, but...

And then there's the class-e stuff

busy, busy, busy. Fixing the internet never ends!

>
> -Toke
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-- 

Dave Täht
CTO, TekLibre, LLC
http://www.teklibre.com
Tel: 1-831-205-9740