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Topic: Why can I still see fq_codel in bmon after turn SQM off?

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Post #1
a2232189
15 Dec 2017, 06:27

I use command 

/etc/init.d/sqm stop

to stop sqm. Here is output:

root@OpenWrt:~# /etc/init.d/sqm stop
SQM: /usr/lib/sqm/stop-sqm: Stopping eth0.2
SQM: ifb associated with interface eth0.2:
SQM: Currently no ifb is associated with eth0.2, this is normal during starting of the sqm system.
SQM: /usr/lib/sqm/stop-sqm: ifb4eth0.2 shaper deleted
SQM: /usr/lib/sqm/stop-sqm: ifb4eth0.2 interface deleted
SQM: /usr/lib/sqm/stop-sqm: Stopping wlan0
SQM: ifb associated with interface wlan0:
SQM: Currently no ifb is associated with wlan0, this is normal during starting of the sqm system.
SQM: /usr/lib/sqm/stop-sqm: ifb4wlan0 shaper deleted
SQM: /usr/lib/sqm/stop-sqm: ifb4wlan0 interface deleted
root@OpenWrt:~# bmon
root@OpenWrt:~# bmon
root@OpenWrt:~# /etc/init.d/sqm stop
root@OpenWrt:~# /etc/init.d/sqm stop
root@OpenWrt:~# /etc/init.d/sqm stop

However, if I use bmon to see network traffic, I can still see fq_codel, which means SQM is not turned off :


lo                                                                                                                                                                                                     bmon 3.5
Interfaces                     x RX bps       pps     %x TX bps       pps     %
>lo                           x      0         0      x      0         0
  eth0                         x 120.59KiB    137      x   9.81KiB    116
    qdisc none (fq_codel)      x      0         0      x   9.35KiB    116
    eth0.1                     x 115.02KiB    117      x   9.34KiB    116
    eth0.2                     x   3.15KiB     20      x     14B        0
  br-lan                       x 114.89KiB    116      x   9.34KiB    116
  wlan0                        x   9.02KiB    115      x 118.67KiB    115
  tun0                         x      0         0      x      0         0
    qdisc none (fq_codel)      x      0         0      x      0         0

Am I missing something here? How can I truely turn SQM off without reboot?

(Last edited by a2232189 on 15 Dec 2017, 06:27)

Post #2
moeller0
15 Dec 2017, 17:32

Erm, please post the output of:

cat /etc/config/sqm
tc -s qdisc
tc -s qdisc

Most likely you see fq_codel as I believe this is the default qdisc in openwrt.

Post #3
a2232189
16 Dec 2017, 03:07

One thing I must metion is that, I uninstalled luci-app-sqm after I posted this topic but before I posted this reply. (sqm-scripts hasn't been uninstalled.) I don't know whether the uninstall action will cause something different so I metioned it here.

root@OpenWrt:~# cat /etc/config/sqm

config queue 'eth1'
    option qdisc 'fq_codel'
    option script 'simple.qos'
    option qdisc_advanced '0'
    option linklayer 'none'
    option interface 'wlan0'
    option download '0'
    option upload '0'
    option enabled '1'

config queue
    option qdisc 'fq_codel'
    option script 'simple.qos'
    option linklayer 'none'
    option interface 'eth0.2'
    option download '0'
    option upload '0'
    option qdisc_advanced '0'
    option enabled '1'

root@OpenWrt:~# tc -s qdisc
qdisc fq_codel 0: dev eth0 root refcnt 2 limit 1024p flows 1024 quantum 300 target 5.0ms interval 100.0ms ecn
Sent 13719269501 bytes 16813727 pkt (dropped 0, overlimits 0 requeues 501)
backlog 0b 0p requeues 501
  maxpacket 13626 drop_overlimit 0 new_flow_count 989 ecn_mark 0
  new_flows_len 0 old_flows_len 0
qdisc mq 0: dev wlan0 root
Sent 721992021 bytes 3568052 pkt (dropped 323, overlimits 0 requeues 199)
backlog 0b 0p requeues 199
qdisc fq_codel 0: dev wlan0 parent :1 limit 1024p flows 1024 quantum 300 target 5.0ms interval 100.0ms ecn
Sent 1866486 bytes 5385 pkt (dropped 0, overlimits 0 requeues 0)
backlog 0b 0p requeues 0
  maxpacket 256 drop_overlimit 0 new_flow_count 0 ecn_mark 0
  new_flows_len 0 old_flows_len 0
qdisc fq_codel 0: dev wlan0 parent :2 limit 1024p flows 1024 quantum 300 target 5.0ms interval 100.0ms ecn
Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
backlog 0b 0p requeues 0
  maxpacket 256 drop_overlimit 0 new_flow_count 0 ecn_mark 0
  new_flows_len 0 old_flows_len 0
qdisc fq_codel 0: dev wlan0 parent :3 limit 1024p flows 1024 quantum 300 target 5.0ms interval 100.0ms ecn
Sent 720099320 bytes 3562538 pkt (dropped 323, overlimits 0 requeues 199)
backlog 0b 0p requeues 199
  maxpacket 7370 drop_overlimit 0 new_flow_count 2710 ecn_mark 0
  new_flows_len 0 old_flows_len 0
qdisc fq_codel 0: dev wlan0 parent :4 limit 1024p flows 1024 quantum 300 target 5.0ms interval 100.0ms ecn
Sent 26215 bytes 129 pkt (dropped 0, overlimits 0 requeues 0)
backlog 0b 0p requeues 0
  maxpacket 256 drop_overlimit 0 new_flow_count 0 ecn_mark 0
  new_flows_len 0 old_flows_len 0
qdisc fq_codel 0: dev tun0 root refcnt 2 limit 1024p flows 1024 quantum 300 target 5.0ms interval 100.0ms ecn
Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
backlog 0b 0p requeues 0
  maxpacket 256 drop_overlimit 0 new_flow_count 0 ecn_mark 0
  new_flows_len 0 old_flows_len 0
root@OpenWrt:~#

Post #4
a2232189
16 Dec 2017, 03:13
moeller0 wrote:

Erm, please post the output of:

cat /etc/config/sqm
tc -s qdisc
tc -s qdisc

Most likely you see fq_codel as I believe this is the default qdisc in openwrt.

So are you suggesting that fq_codel is the default qdisc in openwrt? In other words, I can't verify whether SQM is enable or not by using bmon to see whether there is traffic through fq_codel, right?

(Last edited by a2232189 on 16 Dec 2017, 03:14)

Post #5
moeller0
16 Dec 2017, 21:32
a2232189 wrote:

One thing I must metion is that, I uninstalled luci-app-sqm after I posted this topic but before I posted this reply. (sqm-scripts hasn't been uninstalled.) I don't know whether the uninstall action will cause something different so I metioned it here.

root@OpenWrt:~# cat /etc/config/sqm

config queue 'eth1'
    option qdisc 'fq_codel'
    option script 'simple.qos'
    option qdisc_advanced '0'
    option linklayer 'none'
    option interface 'wlan0'
    option download '0'
    option upload '0'
    option enabled '1'

config queue
    option qdisc 'fq_codel'
    option script 'simple.qos'
    option linklayer 'none'
    option interface 'eth0.2'
    option download '0'
    option upload '0'
    option qdisc_advanced '0'
    option enabled '1'

root@OpenWrt:~# tc -s qdisc
qdisc fq_codel 0: dev eth0 root refcnt 2 limit 1024p flows 1024 quantum 300 target 5.0ms interval 100.0ms ecn
Sent 13719269501 bytes 16813727 pkt (dropped 0, overlimits 0 requeues 501)
backlog 0b 0p requeues 501
  maxpacket 13626 drop_overlimit 0 new_flow_count 989 ecn_mark 0
  new_flows_len 0 old_flows_len 0
qdisc mq 0: dev wlan0 root
Sent 721992021 bytes 3568052 pkt (dropped 323, overlimits 0 requeues 199)
backlog 0b 0p requeues 199
qdisc fq_codel 0: dev wlan0 parent :1 limit 1024p flows 1024 quantum 300 target 5.0ms interval 100.0ms ecn
Sent 1866486 bytes 5385 pkt (dropped 0, overlimits 0 requeues 0)
backlog 0b 0p requeues 0
  maxpacket 256 drop_overlimit 0 new_flow_count 0 ecn_mark 0
  new_flows_len 0 old_flows_len 0
qdisc fq_codel 0: dev wlan0 parent :2 limit 1024p flows 1024 quantum 300 target 5.0ms interval 100.0ms ecn
Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
backlog 0b 0p requeues 0
  maxpacket 256 drop_overlimit 0 new_flow_count 0 ecn_mark 0
  new_flows_len 0 old_flows_len 0
qdisc fq_codel 0: dev wlan0 parent :3 limit 1024p flows 1024 quantum 300 target 5.0ms interval 100.0ms ecn
Sent 720099320 bytes 3562538 pkt (dropped 323, overlimits 0 requeues 199)
backlog 0b 0p requeues 199
  maxpacket 7370 drop_overlimit 0 new_flow_count 2710 ecn_mark 0
  new_flows_len 0 old_flows_len 0
qdisc fq_codel 0: dev wlan0 parent :4 limit 1024p flows 1024 quantum 300 target 5.0ms interval 100.0ms ecn
Sent 26215 bytes 129 pkt (dropped 0, overlimits 0 requeues 0)
backlog 0b 0p requeues 0
  maxpacket 256 drop_overlimit 0 new_flow_count 0 ecn_mark 0
  new_flows_len 0 old_flows_len 0
qdisc fq_codel 0: dev tun0 root refcnt 2 limit 1024p flows 1024 quantum 300 target 5.0ms interval 100.0ms ecn
Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
backlog 0b 0p requeues 0
  maxpacket 256 drop_overlimit 0 new_flow_count 0 ecn_mark 0
  new_flows_len 0 old_flows_len 0
root@OpenWrt:~#

Okay, un-installing luci-app-sqm will not disable running or configured sqm instances. In your case you set the upload and download to zero which effectively disables sqm's shaper (it seems less round about to me to better set "enabled" to zero, but that is just me). Since simple.qos/fq_codel will employ htb as its traffic shaper the fact that you do not see entries for htb in the "tc qdisc" outputs confirms tat sqm is doing nothing.

Post #6
moeller0
16 Dec 2017, 21:33
a2232189 wrote:
moeller0 wrote:

Erm, please post the output of:

cat /etc/config/sqm
tc -s qdisc
tc -s qdisc

Most likely you see fq_codel as I believe this is the default qdisc in openwrt.

So are you suggesting that fq_codel is the default qdisc in openwrt? In other words, I can't verify whether SQM is enable or not by using bmon to see whether there is traffic through fq_codel, right?

As far as I remember, yes fq_codel is openwrt/lede's default qdisc, so simply seeing fq_codel instances is not diagnostic for sqm-scripts one way or the other.

The discussion might have continued from here.