[Cerowrt-devel] Correct syntax for cake commands and atm issues.

Fri Jul 10 15:27:19 EDT 2015

Hi Fred,

On Jul 10, 2015, at 21:14 , Fred Stratton <fredstratton at imap.cc> wrote:

> 
> 
> On 10/07/15 19:46, Sebastian Moeller wrote:
>> Hi Fred,
>> 
>> your results seem to indicate that cake is not active at all, as the latency under load is abysmal (a quick check is to look at the median in relation to the min and the 90% number, in your examples all of these are terrible). Could you please post the result of the following commands on your router:
>> 1) cat /etc/config/sqm
> config queue 'eth1'
>    option qdisc 'fq_codel'
>    option script 'simple.qos'
>    option qdisc_advanced '0'
>    option linklayer ‘none'

	For an ADSL link I could swear link layer ‘none’ is not optimal ;)

>    option enabled '0'
>    option interface 'eth1'
>    option download '0'
>    option upload ‘0'

	Not that it matters as you do not use the sqm-scripts machinery.

> 
> 
>> 2) tc -d qdisc
> qdisc fq_codel 0: dev eth0 root refcnt 2 limit 1024p flows 1024 quantum 300 target 5.0ms interval 100.0ms ecn
> qdisc fq_codel 0: dev eth1 root refcnt 2 limit 1024p flows 1024 quantum 300 target 5.0ms interval 100.0ms ecn
> qdisc mq 0: dev wlan1 root
> qdisc fq_codel 0: dev wlan1 parent :1 limit 1024p flows 1024 quantum 300 target 5.0ms interval 100.0ms ecn
> qdisc fq_codel 0: dev wlan1 parent :2 limit 1024p flows 1024 quantum 300 target 5.0ms interval 100.0ms ecn
> qdisc fq_codel 0: dev wlan1 parent :3 limit 1024p flows 1024 quantum 300 target 5.0ms interval 100.0ms ecn
> qdisc fq_codel 0: dev wlan1 parent :4 limit 1024p flows 1024 quantum 300 target 5.0ms interval 100.0ms ecn
> qdisc mq 0: dev wlan0 root
> qdisc fq_codel 0: dev wlan0 parent :1 limit 1024p flows 1024 quantum 300 target 5.0ms interval 100.0ms ecn
> qdisc fq_codel 0: dev wlan0 parent :2 limit 1024p flows 1024 quantum 300 target 5.0ms interval 100.0ms ecn
> qdisc fq_codel 0: dev wlan0 parent :3 limit 1024p flows 1024 quantum 300 target 5.0ms interval 100.0ms ecn
> qdisc fq_codel 0: dev wlan0 parent :4 limit 1024p flows 1024 quantum 300 target 5.0ms interval 100.0ms ecn
> qdisc cake 8002: dev pppoe-wan root refcnt 2 bandwidth 850Kbit besteffort flows raw

	You should enable the atm link layer accounting on both ingress (ifb4pppoe-wan) and egress (pppoe-wan).

> qdisc ingress ffff: dev pppoe-wan parent ffff:fff1 ----------------
> qdisc cake 8001: dev ifb4pppoe-wan root refcnt 2 bandwidth 11500Kbit besteffort flows atm overhead 40
> 
>> 3) tc -d class show dev pppoe-wan
> class cake 8002:2fa parent 8002:
> 
> 
>> 4) tc -d class show dev ifb4pppoe-wqn
> 
> class cake 8001:6e parent 8001:
>> 5) /etc/init.d/sqm stop
> SQM: Trying to start/stop SQM on all interfaces.
> SQM: run.sh stop
> SQM: /usr/lib/sqm/run.sh SQM for interface eth1 is not enabled, skipping over...
>> 6) /etc/init.d/sqm start
> /etc/init.d/sqm start
> SQM: Trying to start/stop SQM on all interfaces.
> SQM: /usr/lib/sqm/run.sh SQM for interface eth1 is not enabled, skipping over…

	Alas, not activated so this does not give any diagnostic output… Newer sqm-scripts should work with cake and luci-app-sqm also works well to set up cake. Please find the most recent files for sqm-scripts attached. The content of the sqm folder should replace the content of /usr/lib/sqm on your router.
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 The content of sqm.lua should replace /usr/lib/lua/luci/model/cbi/sqm.lua 
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. These should allow you to set up cake from inside the sqm gui (but it is only lightly tested).

> 
>> 
>> hopefully these give some insight what might have happened.
>> 
>> And finally I would love to learn the output of:
>> sh betterspeedtest.sh -4 -H netperf-eu.bufferbloat.net -t 150 -p netperf-eu.bufferbloat.net -n 4 ; sh netperfrunner.sh -4 -H netperf-eu.bufferbloat.net -t 150 -p netperf-eu.bufferbloat.net -n 4
> 
> betterspeedtest.sh not installed

	Too bad, this would be nice as it measures downlink and uplink sequentially instead of simultaneously so it can help figure out if only one direction is improperly shaped. Could I convince you to install Rich’s betterspeedtest.sh script as well, it should be in the same repository as netperfrunner.sh?

> 
> sh betterspeedtest.sh -4 -H netperf-eu.bufferbloat.ne
> t -t 150 -p netperf-eu.bufferbloat.net -n 4 ; sh netperfrunner.sh -4 -H netperf-
> eu.bufferbloat.net -t 150 -p netperf-eu.bufferbloat.net -n 4
> sh: can't open 'betterspeedtest.sh'
> 2015-07-10 20:10:55 Testing netperf-eu.bufferbloat.net (ipv4) with 4 streams down and up while pinging netperf-eu.bufferbloat.net. Takes about 150 seconds.
> Download:  6.8 Mbps
>   Upload:  0.59 Mbps
>  Latency: (in msec, 152 pings, 0.00% packet loss)
>      Min: 73.911
>    10pct: 232.211
>   Median: 308.556
>      Avg: 305.686
>    90pct: 376.183
>      Max: 412.553

	This just shows that latency still is bounded badly...

> 
>> 
>> 
>> Many Thanks & Best Regards
>> 	Sebastian
>> 
>> On Jul 10, 2015, at 20:25 , Fred Stratton <fredstratton at imap.cc> wrote:
>> 
>>> By your command
>>> Rebooted to rerun qdisc script, rather than changing qdiscs from the command-line, so suboptimal process as end-point changed.
>>> 
>>> script configuring qdiscs and overhead 40 on
>>> 
>>> sh netperfrunner.sh -H netperf-eu.bufferbloat.net -p 2.96.48.1
>>> 2015-07-10 18:22:08 Testing netperf-eu.bufferbloat.net (ipv4) with 4 streams down and up while pinging 2.96.48.1. Takes about 60 seconds.
>>> Download:  6.73 Mbps
>>>   Upload:  0.58 Mbps
>>>  Latency: (in msec, 62 pings, 0.00% packet loss)
>>>      Min: 24.094
>>>    10pct: 172.654
>>>   Median: 260.563
>>>      Avg: 253.580
>>>    90pct: 330.003
>>>      Max: 411.145
>>> 
>>> script configuring qdiscs on flows raw
>>> 
>>> sh netperfrunner.sh -H netperf-eu.bufferbloat.net -p
>>> 78.145.32.1
>>> 2015-07-10 18:49:21 Testing netperf-eu.bufferbloat.net (ipv4) with 4 streams down and up while pinging 78.145.32.1. Takes about 60 seconds.
>>> Download:  6.75 Mbps
>>>   Upload:  0.59 Mbps
>>>  Latency: (in msec, 59 pings, 0.00% packet loss)
>>>      Min: 23.605
>>>    10pct: 169.789
>>>   Median: 282.155
>>>      Avg: 267.099
>>>    90pct: 333.283
>>>      Max: 376.509
>>> 
>>> script configuring qdiscs and overhead 36 on
>>> 
>>> sh netperfrunner.sh -H netperf-eu.bufferbloat.net -p
>>> 80.44.96.1
>>> 2015-07-10 19:20:18 Testing netperf-eu.bufferbloat.net (ipv4) with 4 streams down and up while pinging 80.44.96.1. Takes about 60 seconds.
>>> Download:  6.56 Mbps
>>>   Upload:  0.59 Mbps
>>>  Latency: (in msec, 62 pings, 0.00% packet loss)
>>>      Min: 22.975
>>>    10pct: 195.473
>>>   Median: 281.756
>>>      Avg: 271.609
>>>    90pct: 342.130
>>>      Max: 398.573
>>> 
>>> 
>>> On 10/07/15 16:19, Alan Jenkins wrote:
>>>> I'm glad to hear there's a working version (even if it's not in the current build :).
>>>> 
>>>> Do you have measurable improvements with overhead configured (v.s. unconfigured)?
>>>> 
>>>> I've used netperfrunner from CeroWrtScripts, e.g.
>>>> 
>>>> sh netperfrunner.sh -H netperf-eu.bufferbloat.net -p $ISP_ROUTER
>>>> 
>>>> I believe accounting for overhead helps on this two-way test, because a) it saturates the uplink b) about half that bandwidth is tiny ack packets (depending on bandwidth asymmetry).  And small packets have proportionally high overhead.
>>>> 
>>>> (But it seems to only make a small difference for me, which always surprises Seb).
>>>> 
>>>> Alan
>>>> 
>>>> On 10/07/15 15:52, Fred Stratton wrote:
>>>>> You are absolutely correct.
>>>>> 
>>>>> I tried both a numeric overhead value, and alternatively 'pppoe-vcmux'
>>>>> and 'ether-fcs' in the build I crafted based on r46006, which is lupin
>>>>> undeclared version 2. Everything works as stated.
>>>>> 
>>>>> On lupin undeclared version 4, the current release based on r46117, the
>>>>> values were not recognised.
>>>>> 
>>>>> Thank you.
>>>>> 
>>>>> I had cake running on a Lantiq ADSL gateway running the same r46006
>>>>> build. Unfortunately this was bricked by attempts to get homenet
>>>>> working, so I have nothing to report about gateway usage at present.
>>>>> 
>>>>> 
>>>>> 
>>>>> On 10/07/15 13:57, Jonathan Morton wrote:
>>>>>> You're already using correct syntax - I've written it to be quite
>>>>>> lenient and use sensible defaults for missing information. There are
>>>>>> several sets of keywords and parameters which are mutually orthogonal,
>>>>>> and don't depend on each other, so "besteffort" has nothing to do with
>>>>>> "overhead" or "atm".
>>>>>> 
>>>>>> What's probably happening is that you're using a slightly old version
>>>>>> of the cake kernel module which lacks the overhead parameter entirely,
>>>>>> but a more up to date tc which does support it. We've seen this
>>>>>> combination crop up ourselves recently.
>>>>>> 
>>>>>> - Jonathan Morton
>>>>>> 
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> 