Re: [Cake] net-next is OPEN...

["Toke Høiland-Jørgensen" <toke@toke.dk>]

Pete Heist <pete@eventide.io> writes:

>> On Apr 18, 2018, at 7:43 AM, Pete Heist <pete@eventide.io> wrote:
>> 
>> I also think I saw this happen at lower bandwidths as well, when the CPU wasn’t loaded. What I’ll do is re-test on the current version I have at, say, 50Mbit (or to where load drops substantially), then update to the head and test again, and let you know...
>> 
>>> On Apr 17, 2018, at 3:52 PM, Jonathan Morton <chromatix99@gmail.com> wrote:
>>> 
>>>> On 16 Apr, 2018, at 11:55 pm, Pete Heist <pete@eventide.io> wrote:
>>>> 
>>>> I remember that fairness behavior at low RTTs (< 20ms) needed to be either improved or documented
>>> 
>>> The reason for the behaviour, IIRC, was that throughput dropped below 100% when the latency target was reduced too much.  Since then there has been a small change which might improve it a little, so a retest would be reasonable.
>
> At 50mbit I don’t see nearly as much fairness degradation at low RTTs, although there’s some. Even at 100us, “fairness” is around 1.1 (1.0 being perfectly fair) instead of the 2.x I saw at 500mbit. I do not see much of a difference between the latest code (16d7fed, 2018-04-17) and the previous code I tested (7061401, 2017-12-01), if that info is of use.
>
> RTT: tcp_1up upload Mbps / tcp_12up upload Mbps
>
> 7061401 (2017-12-01):
>
>    100us: 23.80 / 25.85
>    1ms: 23.89 / 29.46
>    10ms: 23.93 / 24.66
>    40ms: 23.96 / 24.10
>    100ms: 23.97 / 24.12
>
> 16d7fed (2018-04-17):
>
>    100us: 23.97 / 26.49
>    1ms: 23.89 / 26.27
>    10ms: 23.98 / 26.37
>    40ms: 23.94 / 24.08
>    100ms: 23.97 / 24.12
>
> I can post reports / flent files on request.
>
> So it appears this is CPU related, and not worth exploring further(?)
> and not worth documenting(?) other than that once things have
> stabilized, documenting how Cake degrades under various extreme
> conditions would be informative.

Awesome, thanks for re-testing! :)

-Toke