Re: [Cake] inbound cake or fq_codel shaping fails on cable on netflix reno

[Tristan Seligmann <mithrandi@mithrandi.net>]

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I should note that I think the ER-X is running out of CPU at times in this
configuration, so that may contribute to the weirdness somewhat.

On Tue, 24 Jul 2018 at 20:05 Tristan Seligmann <mithrandi@mithrandi.net>
wrote:

> Here's my results from South Africa. Ping test while running the fast.com
> test, and the tcp_ndown test, running Cake on an EdgeRouter X. I get 140 /
> 140 Mbps on the fast.com test with 1ms unloaded and 6ms loaded.
>
> Not sure why throughput is so low, but I often see something like this on
> artificial bandwidth tests; it peaks close to 200, but then drops back down
> toward the end of the test. I'm shaping to 200 / 200 Mbps with cake which
> is my sold connection speed; the actual link is 1 Gbps active ethernet over
> fibre with the ISP limiting to about 210-220 Mbps.
>
>
> On Tue, 24 Jul 2018 at 17:19 Dave Taht <dave.taht@gmail.com> wrote:
>
>> cdfs help. I also try to encourage sending the flent.gz files too. :)
>>
>> Outbound, to 99% or more of the rate, *with perfect framing* looks great
>> so far, 'cept on crappy cablemodems.
>>
>> I am concerned about recommending values as high as 98% for inbound
>> shaping. We are engineering to
>> the test here (2? 3 flows? on a very short rtt), and need to leave *some*
>> headroom for multiple flows to enter in slow start and get kicked out of it.
>>
>> I'll buy that the old 85% figure made sense in the sub 20Mbit era, and
>> that we only need enough headroom to allow X flows to enter based on the
>> characteristics of the link and typical traffic - 15 new flows per second
>> * per active user/10 ? and cake's response to slow start is more
>> agressive...
>>
>> try a:
>>
>> flent -H flent-london.bufferbloat.net -s .02 --te=download_streams=32 -t
>> '98%' tcp_ndown
>>
>> with htb+fq_codel and cake to see that spike more clearly.
>>
>>
>> On Tue, Jul 24, 2018 at 7:54 AM Kevin Darbyshire-Bryant <
>> kevin@darbyshire-bryant.me.uk> wrote:
>>
>>>
>>>
>>> On 24 Jul 2018, at 14:51, Dave Taht <dave.taht@gmail.com> wrote:
>>>
>>> Now that you can join the party, I note there IS a flent server in
>>> england with irtt on it.
>>>
>>> flent-london.bufferbloat.net
>>>
>>>
>>> Ok, well if you’re desperately interested….. :-)
>>>
>>> Plot I did running to the london server, one shaped at 99% downstream,
>>> the other at 98%…. and I’ve decided to stick at 98% as a result - plot is a
>>> little bit hard to distinguish but I’d say there’s around 8ms avg less
>>> latency-ish between the two.  And an order of magnitude between using
>>> london v fremont :-)
>>>
>>> The upstream barely registers
>>>
>>> # tc -s qdisc show dev ifb4eth0
>>> qdisc cake 801a: root refcnt 2 bandwidth 78400Kbit diffserv3
>>> dual-dsthost nat ingress split-gso rtt 100.0ms ptm overhead 26
>>>
>>>
>>>
>>
>> --
>>
>> Dave Täht
>> CEO, TekLibre, LLC
>> http://www.teklibre.com
>> Tel: 1-669-226-2619
>> _______________________________________________
>> Cake mailing list
>> Cake@lists.bufferbloat.net
>> https://lists.bufferbloat.net/listinfo/cake
>>
>

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