[Codel] [Cake] openwrt build available with latest cake and fq_pie

Dave Taht dave.taht at gmail.com
Sun Jun 14 15:42:27 EDT 2015


On Sun, Jun 14, 2015 at 12:35 PM, Jonathan Morton <chromatix99 at gmail.com> wrote:
>
>> On 14 Jun, 2015, at 21:24, Dave Taht <dave.taht at gmail.com> wrote:
>>
>> Flows, btw, do end quite rapidly in the real world. What was it, 95%
>> of all web flows ended inside of IW10?
>
> It might be worth thinking about how heavily loaded a network needs to be for Codel to trigger on such a flow.  However, with perfect flow isolation, count will start at 1, making it less relevant to the present thread.
>
> Cake will start triggering on a instantly-arrived burst (call it a packet salvo) after 35ms.  Thus, a ten-packet burst will not trigger provided at least 4.5 Mbps is available to that flow.  However, on many links that is still a tall order, since if the flows really are that short, there are probably lots of them in parallel.
>
> A paced burst is much more friendly.  At a 100ms RTT, IW10 could be delivered at 100pps (1.5 Mbps), extending the range of link speeds on which congestion signalling will not occur by at least 3x (and generally more).  Since this greatly reduces the risk of packet loss, it might actually reduce the average time that the sender needs to maintain the connection’s buffers, despite the deliberate 1-RTT delay introduced.

Data point: Quic is presently 10 packet burst, 22 packets paced. Not
that I like it.

>  - Jonathan Morton
>



-- 
Dave Täht
What will it take to vastly improve wifi for everyone?
https://plus.google.com/u/0/explore/makewififast



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