Discussion:
[BUG report] kworker issue on A20 SoC with kernel >= 4.12.0
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Kai
2017-12-28 04:45:00 UTC
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Hardware: cubieboard2, cubietruck, Banana Pi
OS: Armbian, Archlinux with kernel >= 4.12.0 (4.12.x, 4.13.x, 4.14.x)
SoC: A20

Issue description: top shows that kworker constantly eats 8%~13% CPU,
performance sensitive apps run stuttered, comparing to they behave on
4.11.x.

I'm using cb2&ct with archlinux, Banana Pi & Armbian are reported on
Armbian forum, the common ground is A20 SoC, kernels later than 4.12.0,
considered to be a thermal sensor polling related BUG.
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Sebastien Lucas
2017-12-29 08:17:07 UTC
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Hi,

I also have the same problem with a Banana Pi (the very old first one) and
Armbian with kernel 4.13.16-sunxi.

I tried to debug a little and run those lines :

$ echo workqueue:workqueue_queue_work > /sys/kernel/debug/tracing/set_event
$ cat /sys/kernel/debug/tracing/trace_pipe > out.txt
(wait a few secs)
$ grep "10975" out.txt


I got this output : https://pastebin.com/t7Z2e9g0

I see a lot of gc_worker [nf_conntrack] so I'm not sure it's related to the
thermal sensor, imho it's related to network.

I've not tried to connect a serial console and disable all network to see
if that fix the problem. I might do that this weekend if I have some time.

Thanks in advance.
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Kai
2018-01-30 08:58:36 UTC
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It's getting even worse after upgraded to kernel 4.15.0, another kworker
process eats around 35% CPU every 10 secs.


圚 2017幎12月29日星期五 UTC+8䞊午2:04:40Kai写道
Post by Kai
Hardware: cubieboard2, cubietruck, Banana Pi
OS: Armbian, Archlinux with kernel >= 4.12.0 (4.12.x, 4.13.x, 4.14.x)
SoC: A20
Issue description: top shows that kworker constantly eats 8%~13% CPU,
performance sensitive apps run stuttered, comparing to they behave on
4.11.x.
I'm using cb2&ct with archlinux, Banana Pi & Armbian are reported on
Armbian forum, the common ground is A20 SoC, kernels later than 4.12.0,
considered to be a thermal sensor polling related BUG.
--
You received this message because you are subscribed to the Google Groups "linux-sunxi" group.
To unsubscribe from this group and stop receiving emails from it, send an email to linux-sunxi+***@googlegroups.com.
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