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

[Toke Høiland-Jørgensen]

Pete Heist  writes:

>> On Apr 18, 2018, at 7:43 AM, Pete Heist  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  wrote:
>>> 
 On 16 Apr, 2018, at 11:55 pm, Pete Heist  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
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Re: [Cake] net-next is OPEN...

[Pete Heist]

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...

Pete

> On Apr 17, 2018, at 3:52 PM, Jonathan Morton  wrote:
> 
>> On 16 Apr, 2018, at 11:55 pm, Pete Heist  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.
> 
> - Jonathan Morton
> 

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[Cake] net-next is open

[Dave Taht]

http://vger.kernel.org/~davem/net-next.html

Can I garner a few Signed-off-by's?

I will add tested-by for georgio and pete.

-- 

Dave Täht
CEO, TekLibre, LLC
http://www.teklibre.com
Tel: 1-669-226-2619
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