Hello, I'm testing the cerowrt's sqm scripts in Barrier Breaker r41547 and I'm experiencing 100% of CPU usage when being at full bandwidth usage. The process which consumes all the CPU is ksoftirqd.

Because of that, I'm not able to reach the full capacity configured, it stalls at about 7 MB/s. Stopping the sqm scripts, and leaving fq_codel as the only qdisc in the outgoing interface, enables me to reach my full line capacity of 12 MB/s

Is there anything I can do to avoid this CPU bottleneck? My router is a Buffalo WZR-HP-AG300H.

the WZR-HP-AG300H has essentially the same hardware (SoC, wireless, switch, etc.) as the WNDR3800 that CeroWrt targets, so maybe it's an issue with standard OpenWrt using the SQM scripts?

(Last edited by drawz on 15 Jul 2014, 04:04)

I'm having the same problem with the same router...
I've installed the last version of barrier braker in OpenWRT site, but in my case I cant detect who is the responsable.
I already updated everything, hostapd included (that I see in another comment in this forum).
The annoyuing part is when I do a reboot, everything goes to normal for a while (a few hours) then, something ramps near to 100% (I can see the load at htop for exemplo, but none of the services running that I can see where with a high load, or even the sum of these)

At this exact moment:

OpenWrt Barrier Breaker 14.07 | Load: 9.73 8.79 5.67

I made a reboot a few hours ago, and for a two or three hours every thing was ok.

You could try posting on the cerowrt-devel mailing list:
https://lists.bufferbloat.net/listinfo/cerowrt-devel
to get their take on it.

I'm running CC so I'm not sure if it's the same as under BB, but you could try disabling SQM and instead enabling the standard OpenWRT QoS - at least in CC QoS uses the underlying fq_codel.

Please report back here your results both in any feedback from cerowrt and also any difference you find (or not) with QoS.

FWIW BB & AA also use fq_codel for QoS