[Cerowrt-devel] performance numbers from WRT1200AC (Re: Latest build test - new sqm-scripts seem to work; "cake overhead 40" didn't)

[Sebastian Moeller]

Hi Mikael,


On Jun 29, 2015, at 06:58 , Mikael Abrahamsson <swmike at swm.pp.se> wrote:

> On Sun, 28 Jun 2015, Sebastian Moeller wrote:
> 
>> Could you post the result of:
>> 
>> cat /etc/config/sqm
>> 
>> from the router, please? And the output of
>> 
>> /etc/init.d/sqm stop ; /etc/init.d/sqm start
>> 
>> this might give me a clue where to look...
> 
> root at OpenWrt:~# cat /etc/config/sqm
> 
> config queue 'eth1'
>        option script 'simple.qos'
>        option interface 'eth0'
>        option qdisc_advanced '1'
>        option squash_dscp '0'
>        option squash_ingress '0'
>        option ingress_ecn 'ECN'
>        option egress_ecn 'ECN'
>        option qdisc_really_really_advanced '0'
>        option enabled '1'
>        option download '500000'
>        option upload '500000'
>        option qdisc 'cake'
>        option linklayer 'ethernet'
>        option overhead ’42'

	Ah, I see, you are still using tc’s stab mechanism for account of per packet overhead and link layer adjustments instead of cake’s (you need to check the advanced options check box in the link layer adjustments tab, and then select “cake” as the lnk layer adjustment mechanism).

> 
> root at OpenWrt:~# /etc/init.d/sqm stop
> SQM: Trying to start/stop SQM on all interfaces.
> SQM: run.sh stop
> SQM: /usr/lib/sqm/run.sh Stopping SQM on interface: eth0
> SQM: ifb associated with interface eth0:
> SQM: trying to create new IFB: ifb4eth0
> RTNETLINK answers: File exists

	We can ignore this as it is cosmetic.

> SQM: /usr/lib/sqm/stop.sh: Stopping eth0
> SQM: ifb associated with interface eth0:
> SQM: /usr/lib/sqm/run.sh SQM qdiscs on eth0 removed
> root at OpenWrt:~# /etc/init.d/sqm start
> SQM: Trying to start/stop SQM on all interfaces.
> SQM: /usr/lib/sqm/run.sh Queue Setup Script: /usr/lib/sqm/simple.qos
> SQM: ifb associated with interface eth0:
> SQM: trying to create new IFB: ifb4eth0
> RTNETLINK answers: File exists
> SQM: cake
> SQM: Keeping differentiated services code points (DSCP) from ingress.
> SQM: STAB: stab mtu 2047 tsize 512 mpu 0 overhead 42 linklayer ethernet

	Again, this is tc’s stab mechanism and not cake’s. But it should not break I guess...

> 
> This command never completes. I added -x to simple.qos and the RTNETLINK is from:
> 
> + /usr/sbin/ip link add name ifb4eth0 type ifb
> RTNETLINK answers: File exists
> 
> and the last commands that execute are:
> 
> SQM: STAB: stab mtu 2047 tsize 512 mpu 0 overhead 42 linklayer ethernet
> + echo stab mtu 2047 tsize 512 mpu 0 overhead 42 linklayer ethernet
> + get_cake_lla_string
> + STABSTRING=
> + [ tc_stab = cake -a ethernet != none ]
> + sqm_logger
> + logger -t SQM -s

	This is weird, under cerowrt this works; but that call to sqm_logger is not useful anyways, it is either repetitive or empty, so I will just delete it

Best Regards
	Sebastian


> 
> -- 
> Mikael Abrahamsson    email: swmike at swm.pp.se