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I installed Ubuntu 13.10 on a MacBook Pro 10,1. However, after installing, the kworker process consumes over 90% of CPU usage. I tried the following:

  1. (Suggested in this answer) Execute grep . -r /sys/firmware/acpi/interrupts/ to see if any GPEs have high values.
  2. (Suggested in this answer) Under sudo -s, execute echo l > /proc/sysrq-trigger and read the output in dmesg.
  3. (Suggested in this answer) Execute sudo perf record -g -a sleep 10 and read the output in perf report.

For 1, gpe16 had a high value and it kept climbing. I tried disabling gpe16 as suggested in the answer, and the kworker CPU usage went down to 0.0%.

For 2 (without disabling gpe16), dmesg showed no additional information than what was present at boot.

For 3 (without disabling gpe16), it reported the following in red:

-  50.76%      kworker/0:5  [kernel.kallsyms]                        [k] native_read_tsc
   - native_read_tsc
      - 64.72% delay_tsc
           __const_udelay
         + gmux_index_wait_ready.isra.6
      - 35.28% __const_udelay
         + gmux_index_wait_ready.isra.6
-  35.14%      kworker/0:5  [kernel.kallsyms]                        [k] delay_tsc
   - delay_tsc
   - __const_udelay
   - gmux_index_wait_ready.isra.6
      - 59.84% gmux_index_write8
           gmux_notify_handler
           acpi_ev_notify_dispatch
           acpi_os_execute_deferred
           process_one_work
           worker_thread
           kthread
           ret_from_fork
      - 40.16% gmux_index_read8
           gmux_notify_handler
           acpi_ev_notify_dispatch
           acpi_os_execute_deferred
           process_one_work
           worker_thread
           kthread
           ret_from_fork

Questions:

  1. What is gpe16? How do I know that disabling this interrupt for the sake of kworker will not have other consequences?
  2. What information can be gleaned from perf report? Is there something do to with the timestamp on the MacBook Pro?
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1  
This is a Q & A site. As your results might indicate, it's unlikely to get answers here when you group them. What is gpe16 is one question and What information can be gleaned from perf report? is another. A third unclear question is Is there something do to with the timestamp on the MacBook Pro? I recommend splitting your questions up and presenting them singly as this will be more likely to result in answers and won't be so overwhelmingly broad and unclear that your question gets skipped over. I thank you and the community thanks you! –  Elder Geek Feb 27 at 16:57
    
sometimes kworker gets stuck in a loop if you don't have enough swap space allocated as it constantly continues to search for available swapspace that doesn't exist –  mchid Mar 16 at 2:12

1 Answer 1

I know this is an old question, but there are two things you can try.

  1. htop. This is an alternative to top. It adds scrolling and some other useful features, which might help you see a process that might be using a lot of CPU.
  2. System Monitor. This is a built-in application and is the Ubuntu equivalent to Windows Task Manager. It will let you sort by different things and kill tasks, all graphically.
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