[Cake] [Bloat] [Make-wifi-fast] Van Jacobson's slides on timing wheels at netdevconf

Dave Taht dave.taht at gmail.com
Mon Jul 23 11:36:46 EDT 2018

On Mon, Jul 23, 2018 at 5:52 AM Mikael Abrahamsson <swmike at swm.pp.se> wrote:
> On Sat, 21 Jul 2018, Jonathan Morton wrote:
> > An example of such a situation would be sparse flows in DRR++, which is
> > a key part of fq_codel and Cake.  So to implement DRR++ using timing
> > wheels, you have to choose your scheduling horizon carefully so as to
> > minimise the delay to sparse packets.
> At the spring IETF, there was talk from IEEE person about using ethernet
> pause frames to get senders to stop talking for a while. My understanding
> was that this was on microsecond scale or even nanosecond time scales.
> One of the mentions in the presentation was on slide 10 about
> "fat-buffered router". In the data center, these are kind of going away,
> because on-die memory is small and rates are high. A 64x100GE forwarding
> asic might have 16MB of buffer, which is very little buffer for the kind
> of bit rates we're talking here.
> https://www.youtube.com/watch?v=sJMvAqEQCBE 1h44m in (proposed IEEE
> 802.1Qcz work) is the one I am thinking of.

OK, I watched a bit of that. Lot of handwaving.

Prior to that I fast forwarded past BB's l4s thing and looked a little
at PSS, which essentially looked like it was doing FQ between dscp

I think the ietf should just rename itself to being DCTF (the data
center task force) and let some other org arise to take care of the

> Wonder how this would interact with the timing wheel proposed by Van Jacobson.
FIFO queues remain cheap.

I keep hitting reload hoping the video to the talk was up.

> Jacobson?
> --
> Mikael Abrahamsson    email: swmike at swm.pp.se
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Dave Täht
CEO, TekLibre, LLC
Tel: 1-669-226-2619

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