Re: [Cake] 450 up stream test

[Adrian Popescu <adriannnpopescu@gmail.com>]

I've also observed higher packet delay on the second class with a
single stream with a rate limiter. Setting a rate limit of 50mbps
seems to be inducing latency as that stream goes up towards the limit.
I haven't checked if there were other competing streams which were
actually seeing that latency.

On Wed, Apr 22, 2015 at 11:34 AM, Dave Taht <dave.taht@gmail.com> wrote:
> I was finally able to induce "way" collisions and codel was not able
> to successfully control the depth of the queue in this test of 9
> copies of the 50 up test....
>
> root@nuc-client:~/git/iproute2-cake# tc -s qdisc show dev eth0
> qdisc cake 8003: root refcnt 2 bandwidth 920Mbit diffserv4 flows
>  Sent 13826214606 bytes 10775480 pkt (dropped 187301, overlimits
> 7841897 requeues 79)
>  backlog 1732937b 769p requeues 79
>            Class 0     Class 1     Class 2     Class 3
>   rate       920Mbit  862500Kbit     690Mbit     230Mbit
>   target       5.0ms       5.0ms       5.0ms       5.0ms
> interval     105.0ms     105.0ms     105.0ms     105.0ms
> Pk delay         0us      22.0ms         0us        19us
> Av delay         0us      12.0ms         0us         1us
> Sp delay         0us       3.8ms         0us         1us
>   pkts        305686     4248957           0      520011
> way inds           0      504555           0           0
> way miss           3      165303           0           7
> way cols           0        4656           0           0
>   bytes   1040146583 11540379317           0  1730046460
>   drops           38      187176           0          87
>   marks            0           0           0           0
>
> We dont  have a good way to plot a test this extreme, and offloads do
> hurt a lot. I turned off offloads to see what would happen:
>
> root@nuc-client:~/git/iproute2-cake# tc -s qdisc show dev eth0
> qdisc cake 8004: root refcnt 2 bandwidth 920Mbit diffserv4 flows
>  Sent 3147074201 bytes 2948700 pkt (dropped 115035, overlimits 4207356
> requeues 417)
>  backlog 1592366b 1159p requeues 417
>            Class 0     Class 1     Class 2     Class 3
>   rate       920Mbit  862500Kbit     690Mbit     230Mbit
>   target       5.0ms       5.0ms       5.0ms       5.0ms
> interval     105.0ms     105.0ms     105.0ms     105.0ms
> Pk delay         0us      26.2ms         0us         9us
> Av delay         0us      12.2ms         0us         0us
> Sp delay         0us       4.7ms         0us         0us
>   pkts             0     3064884           0          10
> way inds           0      456896           0           0
> way miss           0      106191           0           2
> way cols           0        1085           0           0
>   bytes            0  3322825235           0        1186
>   drops            0      115035           0           0
>   marks            0           0           0           0
>
>
> --
> Dave Täht
> Open Networking needs **Open Source Hardware**
>
> https://plus.google.com/u/0/+EricRaymond/posts/JqxCe2pFr67
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