Origin of a kworker-thread

Question

On my newly installed system using kernel 3.2 I see a kworker-thread which is constantly consuming CPU. I\'d like to find out which part of kernel/module has created this workqu

Answer 1

kworker / watchdog causing high load regularly when not on cable power - workaround

Had kworker (cause kernel_thread_helper+0x6/0x10 ?) thread 1 spiking to 100% of a cpu for 1 second every 5 seconds only if laptop powered by cable. No problems on battery power. Did not matter if battery fully charged.

It more or less came out of the blue, so I guess the recent Ubuntu update was the cause (3.2.0-55-generic-pae now).

Was looking for half a day, trying to figure out wft the root cause is and endet up trying to disable all acpi interrupts, which did not matter.

Adding GRUB_CMDLINE_LINUX_DEFAULT=”acpi=off” to /etc/defaults/grub helped in the end.

As I discovered right now I added it with these exact special unicode quotes, which might explain the incompatibility with "quiet splash" (with default quotes) which puzzled me. I have to look into some more grub issues (boot menu not being displayed however I try, default entry config not used ...) so I will leave that testing for later.

PS: a week later, the problem is back (without restart, only suspend in between). There might be a correlation to using an usb mouse. Power down/power up helped (restart did not). Threw all grub options away. I am expecting the problem to show up again sometime.

PPS: Took some time (half a year), but it is back again after a resume from ram. No recent updates, just plugging/unplugging power, as I often do. No USB devices plugged/unplugged. Had a totem running (but nothing playing) during suspend. Power down/power up with power cable plugged did not help, power down/power up with power cable unplugged did.