[Make-wifi-fast] [Bloat] Van Jacobson's slides on timing wheels at netdevconf
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.
> Mikael Abrahamsson email: swmike at swm.pp.se
> Bloat mailing list
> Bloat at lists.bufferbloat.net
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