HalexPereira

Q: kernel_task is using 100% CPU when waking from sleep

Since updating my 13" mid-2013 MacBook Air to Mavericks, there's this issue that's been happening when I wake the computer up from sleep. A proccess called kernel_task uses 100% CPU (a whole core) and hangs there until the computer is restarted. This doesn't make the computer unresponsive, but it kills battery life.

 

So far, I've tried the following:

 

1. Resetting SMC, NVRAM and PRAM: no effect.

2. Safe Boot: the issue doesn't happen.

3. Deleting old apps/plugins: issue persists.

4. Closing all apps doesn't solve issue after it takes place.

5. Repairing permissions: no effect.

6. Apple Diagnostics: no issue found in hardware.

7. No kernel extensions from third-parties are installed (there are 120 kext, according to Terminal, but they all come from Apple).

8. Everything is up to date.

9. Only external plugin installed is Flash.

 

Given these, I reckon it's something software-related. Any tips on solving this would be welcome — things to look for in Console logs would be greatly appreciated.

MacBook Air (13-inch Mid 2013), OS X Mavericks (10.9)

Posted on Oct 28, 2013 12:03 PM

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Q: kernel_task is using 100% CPU when waking from sleep

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  • by SundanceX,

    SundanceX SundanceX Jan 13, 2014 7:38 AM in response to milo jah
    Level 1 (5 points)
    Jan 13, 2014 7:38 AM in response to milo jah

    I too have reproduced this here three times in a row. The CPU goes to 100% after waking up but comes down to normal levels afer a minute.

  • by kuerbiskopf,

    kuerbiskopf kuerbiskopf Jan 13, 2014 7:39 AM in response to milo jah
    Level 1 (2 points)
    Jan 13, 2014 7:39 AM in response to milo jah

    I could reproduce this issue with milo jahs method. Definitely audio related.

  • by Prophet-123,

    Prophet-123 Prophet-123 Jan 13, 2014 10:40 PM in response to HalexPereira
    Level 1 (0 points)
    Jan 13, 2014 10:40 PM in response to HalexPereira

    any fix for this yet? I have to almost reboot my late 2013 rMBP everytime it wakes from sleep. Godam it!

  • by cyclix86,

    cyclix86 cyclix86 Jan 13, 2014 11:49 PM in response to milo jah
    Level 1 (0 points)
    Jan 13, 2014 11:49 PM in response to milo jah

    I have reproduced this on a late 2013 Retina MacBook Pro 13" (Mavericks 10.9.1) using the Sound settings window method. Have done it about 7 times to test, and it happens every time. The processor usage stays at 100% on core 0 for as long as the sound window is open (and by extension, as long as the microphone is enabled). CPU usage only comes back down to 0 about 30 seconds after closing the System Prefs window. Opening Sound prefs normally results in no abnormal processor usage.

     

    I tried substituting the Sound | Input preference pane with plugging my earpods (with mic). With no programs running (not even system preferences) I observed the following with 100% repeatability:

    Plug in Earpods -> close lid -> wait 60 seconds -> open lid -> kernel_task = 100% on core 0 -> unplug earpods -> wait ~5 seconds -> kernel_task = ~3% on core 0

     

    The following also happens if you plug in the earpods while the machine is asleep, or in a small ~5 second window after waking the machine. If you plug them AFTER this window (once the machine is fully awake) everything works normally (~3% CPU usage from kernel_task). This seems to relate to the small window of activity normally seen by kernel_task when waking from sleep. From my experience, kernel_task uses 100% of core 0 when waking from sleep for about 5 seconds (may be machine dependant) before coming back down to around 0. This is normal, and is probably related with the hardware waking up. If, however, you plug the earpods in during this window (or if they were in when it was woken from sleep), this activity will continue indefinitely, or at least as long I was prepared to wait.

     

    These are my experiences, as far I can tell they are 100% repeatable on my machine. Would be interested to see if anyone else has similar experiences.

  • by Prophet-123,

    Prophet-123 Prophet-123 Jan 14, 2014 2:41 AM in response to cyclix86
    Level 1 (0 points)
    Jan 14, 2014 2:41 AM in response to cyclix86

    I was able to instantly get rid off the problem by unplugging my original Apple USB ethernet dongle. I don't know if that helps.

  • by oradoe,

    oradoe oradoe Jan 14, 2014 4:58 AM in response to cyclix86
    Level 1 (0 points)
    Jan 14, 2014 4:58 AM in response to cyclix86
  • by Sharp-man,

    Sharp-man Sharp-man Jan 14, 2014 6:32 AM in response to cyclix86
    Level 1 (59 points)
    iPhone
    Jan 14, 2014 6:32 AM in response to cyclix86

    Exactly what I see. At least for the late 2013 MacBook Pro 13" Retina (and maybe the mid-2013 MBAs), this appears to be related to the microphone - maybe due to the new audio chipset. It is 100% repeatable.

  • by adilbek,

    adilbek adilbek Jan 14, 2014 10:41 AM in response to HalexPereira
    Level 1 (0 points)
    Jan 14, 2014 10:41 AM in response to HalexPereira

    I reproduced this issue (plug earpods -> close lid -> ...etc.) on 3 different rMBPs in the apple store and reported to the technician. He opened a work order and said that he sent an email to Apple engineers. This was before Christmas so I am hoping to receive an answer any time now. Most likely, Apple will incorporate a fix in their next round of OS X update.

  • by gattol,

    gattol gattol Jan 15, 2014 12:57 AM in response to HalexPereira
    Level 1 (0 points)
    Jan 15, 2014 12:57 AM in response to HalexPereira

    My bug report has been closed ad a duplicate of 15046435

  • by antony-m,

    antony-m antony-m Jan 15, 2014 5:55 AM in response to gattol
    Level 1 (0 points)
    Jan 15, 2014 5:55 AM in response to gattol

    Mine too.

  • by milo jah,

    milo jah milo jah Jan 15, 2014 11:25 AM in response to antony-m
    Level 1 (10 points)
    Jan 15, 2014 11:25 AM in response to antony-m

    I just checked and as of 1PM EST, my ticket still exists...

     

    15724482

  • by alexfsu,

    alexfsu alexfsu Jan 15, 2014 2:49 PM in response to HalexPereira
    Level 1 (0 points)
    Jan 15, 2014 2:49 PM in response to HalexPereira

    same cpu problem

  • by MattRehm,

    MattRehm MattRehm Jan 15, 2014 5:17 PM in response to HalexPereira
    Level 1 (0 points)
    Jan 15, 2014 5:17 PM in response to HalexPereira

    I have a new MBA not even days old with a fresh install of 10.9, I have never plugged in any headphones of any kind. I do have the exact same problem of 100% CPU on one core when the MBA wakes from sleep. I am now set to rebooting my laptop several times a day.. I am also looking for a fix..

  • by Karim_Geiger,

    Karim_Geiger Karim_Geiger Jan 16, 2014 5:01 AM in response to HalexPereira
    Level 1 (0 points)
    Jan 16, 2014 5:01 AM in response to HalexPereira

    I'm just writing this to let you know I've got the same problem. I've tried reinstalling OS X several times. At the moment my MacBook Air Mid 2013 is sent to the Apple Support. Hope they'll provide a fix. This is absolutely inappropriate behaviour.

  • by bausi,

    bausi bausi Jan 16, 2014 7:17 AM in response to John_Raz
    Level 1 (10 points)
    Jan 16, 2014 7:17 AM in response to John_Raz

    try the thing with ther kext  as seen on page 3 of this thread i guess from 10.8.5! That REALLY  solved my issue! MBA2013

     

     

    Here how i have replace the AppleHDA.kext driver on my MacBookAir 13" (2013):

     

    sudo mv /System/Library/Extensions/AppleHDA.kext /System/Library/Extensions/AppleHDA.kext.disabled sudo cp -pr AppleHDA.10.8.5.kext /System/Library/Extensions/AppleHDA.kext sudo chown -R root:wheel /System/Library/Extensions/AppleHDA.kext sudo touch  /System/Library/Extensions 

     

    Then reboot

     

    Here the link to AppleHDA driver of Mountain Lion 10.8.5:https://dl.dropboxusercontent.com/u/112112/AppleHDA.10.8.5.kext.zip

     

     

    cheers.mate!

     

    Message was edited by: bausi

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