[Cake] commit 0d8f30 breaks ingress mode
George Amanakis
gamanakis at gmail.com
Mon Dec 25 01:48:13 EST 2017
I think I found out why using veth scripts this didn't show up:
dslreports.com generates traffic that is classified as "bulk" by cake.
I modified rrul_be_nflows.conf to classify all generated traffic as
CS1. Ran a simulation where one client downloads simultaneously from 4
servers, 24 flows each. The latency is huge ~1000ms in this case.
If traffic is classified as "best-effort (CS0)", the latency is <50ms.
tc -s stats:
qdisc cake 1: dev mbox.l root refcnt 2 bandwidth 1800Kbit diffserv3
triple-isolate ack-filter rtt 100.0ms raw
Sent 5750764 bytes 75026 pkt (dropped 64, overlimits 10957 requeues
0)
backlog 0b 0p requeues 0
memory used: 45324b of 4Mb
capacity estimate: 1800Kbit
Bulk Best Effort Voice
thresh 112496bit 1800Kbit 450Kbit
target 161.5ms 10.1ms 40.4ms
interval 323.0ms 105.1ms 135.4ms
pk_delay 278us 237us 1us
av_delay 26us 66us 0us
sp_delay 0us 2us 0us
pkts 33229 41857 4
bytes 2526174 3228646 168
way_inds 1850 2538 0
way_miss 121 355 1
way_cols 0 0 0
drops 0 0 0
marks 0 0 0
ack_drop 43 21 0
sp_flows 0 1 1
bk_flows 0 0 0
un_flows 0 0 0
max_len 94 722 42
qdisc cake 1: dev mbox.r root refcnt 2 bandwidth 9Mbit diffserv3
triple-isolate ingress rtt 100.0ms raw
Sent 107963942 bytes 77681 pkt (dropped 24977, overlimits 161469
requeues 0)
backlog 0b 0p requeues 0
memory used: 4199760b of 4Mb
capacity estimate: 9Mbit
Bulk Best Effort Voice
thresh 562496bit 9Mbit 2250Kbit
target 32.3ms 5.0ms 8.1ms
interval 127.3ms 100.0ms 103.1ms
pk_delay 1.9s 14.5ms 754us
av_delay 926.5ms 4.6ms 14us
sp_delay 11.0ms 1us 11us
pkts 48809 53846 3
bytes 73487282 72197216 126
way_inds 1894 1763 0
way_miss 100 348 1
way_cols 0 0 0
drops 12843 12134 0
marks 0 0 0
ack_drop 0 0 0
sp_flows 96 1 1
bk_flows 0 0 0
un_flows 96 0 0
max_len 3028 3028 42
George
On Mon, 2017-12-25 at 00:35 -0500, George Amanakis wrote:
> Dear All,
>
> merry christmas to the list members!
>
> I was doing some real-world testing using dslreports.com/speedtest
> with
> my 10/2mbps comcast cable line, and found out by bisecting that
> commit 0d8f30faa3d4bb2bc87a382f18d8e0f3e4e56ea (Dynamically adjust
> sojourn target according to flow count and serialisation delay)
> deteriorates latency even in ingress mode.
>
> In real-world, with 16 flows downloading from dslreports.com ping
> times
> are >500ms. This has never been the case with ingress mode before. I
> don't know yet why this didn't show up with the veth scripts.
>
> In sch_cake.c changing over_target to its pre 0d8f30 value "sojourn >
> p->target" brings ping times down to <50ms.
>
> tc -s qdisc show:
> qdisc cake 801f: dev ens4 root refcnt 2 bandwidth 12200Kbit diffserv3
> dual-dsthost wash ingress rtt 100.0ms noatm overhead 18 via-ethernet
> mpu 64
> Sent 23963379 bytes 17137 pkt (dropped 35, overlimits 32166 requeues
> 0)
> backlog 0b 0p requeues 0
> memory used: 920832b of 4Mb
> capacity estimate: 12200Kbit
> Bulk Best Effort Voice
> thresh 762496bit 12200Kbit 3050Kbit
> target 23.8ms 5.0ms 6.0ms
> interval 118.8ms 100.0ms 101.0ms
> pk_delay 527.5ms 594us 42us
> av_delay 315.3ms 144us 0us
> sp_delay 1us 1us 0us
> pkts 16197 954 21
> bytes 23412978 600744 2647
> way_inds 0 0 0
> way_miss 105 62 3
> way_cols 0 0 0
> drops 35 0 0
> marks 335 3 0
> ack_drop 0 0 0
> sp_flows 0 0 0
> bk_flows 0 0 1
> un_flows 0 0 0
> max_len 4542 3392 254
>
> qdisc cake 8020: dev ens3 root refcnt 2 bandwidth 2500Kbit diffserv3
> dual-srchost nat wash ack-filter rtt 100.0ms noatm overhead 18 via-
> ethernet mpu 64
> Sent 2890199 bytes 15496 pkt (dropped 20, overlimits 4773 requeues
> 0)
> backlog 0b 0p requeues 0
> memory used: 41764b of 4Mb
> capacity estimate: 2500Kbit
> Bulk Best Effort Voice
> thresh 156248bit 2500Kbit 625Kbit
> target 116.3ms 7.3ms 29.1ms
> interval 232.6ms 102.3ms 124.1ms
> pk_delay 0us 70.0ms 0us
> av_delay 0us 45.2ms 0us
> sp_delay 0us 5.7ms 0us
> pkts 0 15515 1
> bytes 0 2891673 42
> way_inds 0 0 0
> way_miss 0 141 1
> way_cols 0 0 0
> drops 0 0 0
> marks 0 55 0
> ack_drop 0 20 0
> sp_flows 0 0 0
> bk_flows 0 1 0
> un_flows 0 0 0
> max_len 0 4542 42
>
> Could somebody confirm this?
>
>
> George
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