Another nugget from the notes
(http://yuba.stanford.edu/~bspang/buffer-sizing-meeting/notes/):
Chuanxiong Guo, Bytedance
Talked about buffering in Bytedance’s datacenters. The top of rack switches
have buffers of 12-32MB, and the aggregation switches have larger buffers of
several GB. Were hoping to use ECN to reduce buffers for aggregation switches,
but argued that precise ECN marking on egress queue length in VoQs is hard.
However, Arista and Barefoot said they’ve fixed this using the packet latency
instead of queue length for ECN.
This looks like an argument for fq_codel/cake's use of time instead of queue
length, OR an argument for fq, because in a non-overwhelmed fq_system the local
bucket's queue length should be somewhat stronger correlated with the sojurn
times, than the sojurn time of a packet though a shared queue, no?
Best Regards
Sebastian
> On Aug 24, 2019, at 09:54, Jesper Dangaard Brouer <bro...@redhat.com> wrote:
>
> On Fri, 23 Aug 2019 10:13:39 -0700
> Simon Barber <si...@superduper.net> wrote:
>
>>> On Aug 23, 2019, at 9:07 AM, Dave Taht <dave.t...@gmail.com> wrote:
>>>
>>> There's some good preso from various representatives in the dc market here.
>>>
>>> The p4 stuff, in particular (from barefoot) is looking impressive.
>>>
>>> http://yuba.stanford.edu/~bspang/buffer-sizing-meeting/
>
> I followed the link to the animation of AIMD (Additive
> Increase/Multiplicative Decrease), that was really cool!
>
> https://dabh.github.io/network_animations/
>
> --
> Best regards,
> Jesper Dangaard Brouer
> MSc.CS, Principal Kernel Engineer at Red Hat
> LinkedIn: http://www.linkedin.com/in/brouer
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