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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:

(a) What is gpe16? How do I know that disabling this interrupt for the sake of kworker will not have other consequences?

(b) What information can be gleaned from perf report? Is there something do to with the timestamp on the MacBook Pro?

share|improve this question
    
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 2 days ago

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