[Cerowrt-devel] cerowrt-3.10.2-1 dev release + owamp

[Fred Stratton]

On 31 Jul 2013, at 23:14, Sebastian Moeller <moeller0 at gmx.de> wrote:

> Hi Fred,
> 
> thanks a lot.
> 
> 
> On Jul 31, 2013, at 23:37 , Fred Stratton <fredstratton at imap.cc> wrote:
> 
>> tc -s -d class show dev ge00
>> 
>> class htb 1:10 parent 1:1 leaf 110: prio 0 quantum 1500 rate 700000bit ceil 700000bit burst 1599b/1 mpu 0b overhead 0b cburst 1599b/1 mpu 0b overhead 0b level 0 
>> Sent 15809014 bytes 115190 pkt (dropped 4733, overlimits 0 requeues 0) 
>> rate 3616bit 3pps backlog 0b 0p requeues 0 
>> lended: 115190 borrowed: 0 giants: 0
>> tokens: 263560 ctokens: 263560
>> 
>> class htb 1:1 root rate 700000bit ceil 700000bit burst 1599b/1 mpu 0b overhead 0b cburst 1599b/1 mpu 0b overhead 0b level 7 
>> Sent 15809014 bytes 115190 pkt (dropped 0, overlimits 0 requeues 0) 
>> rate 3616bit 3pps backlog 0b 0p requeues 0 
>> lended: 0 borrowed: 0 giants: 0
>> tokens: 263560 ctokens: 263560
>> 
>> class fq_codel 110:1b8 parent 110: 
>> (dropped 0, overlimits 0 requeues 0) 
>> backlog 0b 0p requeues 0 
>>  deficit 84 count 0 lastcount 0 delay 10us
>> 
>> 
>> 
>> tc -s -d class show dev ifb0
>> class htb 1:10 parent 1:1 leaf 110: prio 0 quantum 1500 rate 7000Kbit ceil 7000Kbit burst 1598b/1 mpu 0b overhead 0b cburst 1598b/1 mpu 0b overhead 0b level 0 
>> Sent 192992612 bytes 168503 pkt (dropped 0, overlimits 0 requeues 0) 
>> rate 17096bit 4pps backlog 0b 0p requeues 0 
>> lended: 168503 borrowed: 0 giants: 0
>> tokens: 27454 ctokens: 27454
>> 
>> class htb 1:1 root rate 7000Kbit ceil 7000Kbit burst 1598b/1 mpu 0b overhead 0b cburst 1598b/1 mpu 0b overhead 0b level 7 
>> Sent 192992612 bytes 168503 pkt (dropped 0, overlimits 0 requeues 0) 
>> rate 17096bit 4pps backlog 0b 0p requeues 0 
>> lended: 0 borrowed: 0 giants: 0
>> tokens: 27454 ctokens: 27454
>> 
>> class fq_codel 110:cc parent 110: 
>> (dropped 10, overlimits 0 requeues 0) 
>> backlog 0b 0p requeues 0 
>>  deficit -198 count 1 lastcount 1 ldelay 2.3ms
>> class fq_codel 110:1d9 parent 110: 
>> (dropped 0, overlimits 0 requeues 0) 
>> backlog 0b 0p requeues 0 
>>  deficit 226 count 0 lastcount 0 ldelay 2us
>> class fq_codel 110:1de parent 110: 
>> (dropped 0, overlimits 0 requeues 0) 
>> backlog 0b 0p requeues 0 
>>  deficit 238 count 0 lastcount 0 ldelay 10us
>> class fq_codel 110:345 parent 110: 
>> (dropped 0, overlimits 0 requeues 0) 
>> backlog 0b 0p requeues 0 
>>  deficit 226 count 0 lastcount 0 delay 9us
>> 
>> I changed the hard coded values in /usr/lib/aqm/functions.sh to arbitrary values, rebooted and obtained the same results. Both reflect the 7000kbit/s down and 700kbit/s up I entered in the window.
> 
> 	What is the line rate as read out from the del modem or specified in your contract?

Speedtest.net shows the rate as circa 8.7 megabits/s down, 1 megabit/s up. Line has radio frequency interference from unidentified sources.. Target snr upped to 12 deciBel.  Line can sustain 10 megabits/s with repeated loss of sync.at lower snr.  Contract is for 'up to 20megabits/s'.  850 metres from exchange. Line length circa 1.2km.


> 
>> I ticked the adsl box. Altering the value in functions.sh and unticking the box, with reboot, produced the same outcome.
> 
> 	This nicely shows I screwed up my testing (and or forgot to reboot between changes). Or I did try too high a data rate (initially 97% of the raw link rate)
> 
> 
>> 
>> 
>> 
>> traceroute google.com
>> traceroute: Warning: google.com has multiple addresses; using 173.194.41.128
>> traceroute to google.com (173.194.41.128), 64 hops max, 52 byte packets
>> 1  172.30.42.1 (172.30.42.1)  0.631 ms  0.323 ms  0.249 ms
>> 2  * * *
>> 3  10.1.3.234 (10.1.3.234)  22.596 ms  21.241 ms  22.392 ms
>> 4  * 10.1.3.214 (10.1.3.214)  27.018 ms  26.703 ms
>> 5  10.1.4.249 (10.1.4.249)  29.682 ms  28.923 ms  27.479 ms
>> 6  * * *
>> 7  * 209.85.252.186 (209.85.252.186)  30.379 ms *
>> 8  72.14.238.55 (72.14.238.55)  25.745 ms  25.345 ms  25.594 ms
>> 9  lhr08s03-in-f0.1e100.net (173.194.41.128)  27.566 ms  27.390 ms  27.663 ms
>> 
>> mtr shows packet losses at hops 2-5 
>> 10.1.3.* are Internet Watch Foundation.
> 
> 	This looks pretty reasonable for an adsl link (could be way worse with higher interleaving)
> 
>> 
>> Netalyzr was used. I appreciate it is an imperfect metric.

OK.  Like the ping train idea. Cannot get netperf 2.6.0 to build on Ubuntu 12.04
> 
> 	Well, I ran into this issue before. In short netalyzr's worst case delay numbers do not seem to reflect how an fq_codelled connection feels.  
> Netalyzr uses an unresponsive UDP probe to force the bottleneck router's buffers to fill up;  with unresponsiveness being a property no sane flow over the intent should exhibit. Codel/fq_codel is tailored for responsive flows and will only gradually increase its drop frequency so responsive TCP flows will be controlled gently and keep link utilization high. Given enough time codel will also rein in an unresponsive flows. But netalyzr's probe duration is too short for that to be happening during netalyzr's runtime.
> Fq_codel in my experience does a decent job at keeping interactivity high even with competing traffic like netalyzr (so turn a ping train against say 10.1.3.234 while netalyzr runs or try netperf-wrapper  in addition). 
> So netalyzr really probes the worst case buffer depth against basically a "denial of service" type of load; I am not fully sure what the expectancy on the disc here should be.
> 
> 
> best
> 	Sebastian
> 
> 
>> 
>> 
>> 
>> 
>> 
>> 
>> On 31 Jul 2013, at 21:38, Sebastian Moeller <moeller0 at gmx.de> wrote:
>> 
>>> tc -s -d class show dev ge00
>> 
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>