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 joeyjohnson,

    joeyjohnson joeyjohnson Jan 3, 2014 11:48 AM in response to Herbygold
    Level 1 (12 points)
    Photos for Mac
    Jan 3, 2014 11:48 AM in response to Herbygold

    Herby, you are talking rubbish I am afraid. "One work around work everyware"......... Yeah? What about on a **** iMac, where you can't close it?! It is way deeper than any of these random ideas, which may work on one machine, but they are not THE cure, or THE workaround at all. The only workaround I have found so far in my case, is to shut my computer down and walk the dogs in the field. When I do that, the kernel task doesn't occur as the machine is off. Not sure if the dogs have anything to do with it.

  • by Herbygold,

    Herbygold Herbygold Jan 3, 2014 12:03 PM in response to HalexPereira
    Level 1 (0 points)
    Jan 3, 2014 12:03 PM in response to HalexPereira

    ....you are right! i had this only on MacBook Air´s and -Pro´s, sorry!

    But there it works.

    All kind of workarounds are a shame for apple. If i see this long thread an other postings it looks like this is a big problem for a significant % of users. Why apple did not recognize this in the Beta test and now no change with 10.9.1....

  • by joeyjohnson,

    joeyjohnson joeyjohnson Jan 3, 2014 12:08 PM in response to Herbygold
    Level 1 (12 points)
    Photos for Mac
    Jan 3, 2014 12:08 PM in response to Herbygold

    Couldn't agree more. Apple clearly are nothing like the company they once were. I think we are long overdue a new "Apple" in the market place.  I personally hope one comes along

  • by kuerbiskopf,

    kuerbiskopf kuerbiskopf Jan 5, 2014 7:32 AM in response to HalexPereira
    Level 1 (2 points)
    Jan 5, 2014 7:32 AM in response to HalexPereira

    does this have to do anything with the audio chip? It seems to happen on 2013 models more often. They also have a new audio chip: Cirrus 4208 CRZ while the older models have a Cirrus 4207

     


  • by Badazrael,

    Badazrael Badazrael Jan 5, 2014 8:49 AM in response to HalexPereira
    Level 1 (0 points)
    Jan 5, 2014 8:49 AM in response to HalexPereira

    I found a temporary Solution for the kernel_task Problem.

     

    (If you dont want to plug the power cable on and off.)

     

    I bought a mini fan for about 10 € put it next to my macbook pro and turned it to the direction where the battery is. Wait a minute and watch in your activity monitor how the kernel_task slows down from 200% to 4,3 or something like that.. The only thing whats annoying is the sound wich comes from the fan. But thats a small price to pay :-)

     

    I think another solution would be to completely delete your hardrive and install Snow Leopard.

    But im to lazy to try that out so i just stick with my fan solution.

     

    I have this setup for a year now and never had any kernel_task overheating (or whatever you call it) problems again. (even in games with much cpu usage)

  • by drewrob26,

    drewrob26 drewrob26 Jan 5, 2014 9:00 AM in response to kuerbiskopf
    Level 1 (0 points)
    Jan 5, 2014 9:00 AM in response to kuerbiskopf

    I had that exact same suspicion, both the 2013 rMBP and MBA use that chip and they are the computers with this issue.

  • by kuerbiskopf,

    kuerbiskopf kuerbiskopf Jan 5, 2014 11:20 AM in response to Badazrael
    Level 1 (2 points)
    Jan 5, 2014 11:20 AM in response to Badazrael

    if that solves you problem, then you have a hardware issue. Your MacBook could be old and there could be dust in your Mac. High CPU usage of kernel_task is a sign of overheating.

  • by wintertc,

    wintertc wintertc Jan 6, 2014 9:20 AM in response to HalexPereira
    Level 1 (0 points)
    Jan 6, 2014 9:20 AM in response to HalexPereira

    Type this into terminal:  sudo killall coreaudiod

     

    I had issues streaming music to my appletv before (pre-itunes radio) and came across this command for "resetting" the audio stuff that runs in the background.  It also works at getting rid of the 100% kernel for me.

  • by blue_dabudie,

    blue_dabudie blue_dabudie Jan 6, 2014 11:48 AM in response to wintertc
    Level 1 (0 points)
    Jan 6, 2014 11:48 AM in response to wintertc

    "sudo killall coreaudiod" is a really bad idea - it will crash running applications.  It also doesn't solve the problem.

     

     

    Apple, please tell us, when are you going to fix this ridiculous bug?

  • by wintertc,

    wintertc wintertc Jan 6, 2014 12:27 PM in response to blue_dabudie
    Level 1 (0 points)
    Jan 6, 2014 12:27 PM in response to blue_dabudie

    It worked for me and I just had to hit play on itunes radio to get it back up and running.  Nothing crashed for me, but the only application playing audio at the time was itunes so YMMV.  Also it is another option for those that don't want to restart.  I tried unplugging my headphones and putting to sleep, but it did not work for me.

     

    Edit:

    Also at the time I was running the below applications and nothing crashed.

    Finder

    Endnote

    iCal

    Notes

    iMessage

    Mail

    iTunes

    Safari

    Mathematica

    Matlab

    Excel

    Powerpoint

    Activity Monitor

    Adobe Acrobat

  • by Badazrael,

    Badazrael Badazrael Jan 7, 2014 1:58 AM in response to kuerbiskopf
    Level 1 (0 points)
    Jan 7, 2014 1:58 AM in response to kuerbiskopf

    Thanks for the Tip. Opened my MacBook Pro, found a lot of dust, got rid of it and now it all works fine (without the mini fan).

  • by neuroman_cer,

    neuroman_cer neuroman_cer Jan 7, 2014 8:51 AM in response to HalexPereira
    Level 1 (0 points)
    Jan 7, 2014 8:51 AM in response to HalexPereira

    really seems to be something with sound: I had the apple earpods plugged in, when I noticed the kernel_task eating 100% for a long time... when I read the thread I pulled them out - viola! gone! plugged them back in, but the process did not come up again. so, it's maybe two or more things that have to come together...? still: an anoying bug...

    (13" MBPr late 2013, 2.6Ghz i5)

  • by Marc Bejarano,

    Marc Bejarano Marc Bejarano Jan 7, 2014 1:18 PM in response to HalexPereira
    Level 1 (5 points)
    iOS Apps
    Jan 7, 2014 1:18 PM in response to HalexPereira

    i just came across this after coming out of sleep, like everyone else here.  it wasn't the first time, but it was the first time i bothered to search for others in my bood.  i have a similar powermetrics.txt snippet:

    ---

    **** Session Interrupt distribution ****

     

    CPU 0:

        Vector 0x20(): 0.00 interrupts/sec

        Vector 0x46(SMC): 0.25 interrupts/sec

        Vector 0x49(MacBookAir6,2): 20.42 interrupts/sec

        Vector 0x92(IGPU): 322.54 interrupts/sec

        Vector 0x94(XHC1): 114.36 interrupts/sec

        Vector 0x95(pci8086,9c3a): 0.03 interrupts/sec

        Vector 0x96(HDEF): 29171.14 interrupts/sec

        Vector 0x97(ARPT): 77.10 interrupts/sec

        Vector 0x98(CMRA): 0.00 interrupts/sec

        Vector 0x9d(NHI0): 0.85 interrupts/sec

        Vector 0x9e(SSD0): 46.15 interrupts/sec

        Vector 0xdd(TMR): 876.63 interrupts/sec

        Vector 0xde(IPI): 250.64 interrupts/sec

    ---

     

    before i got a chance to play around further, i switched to another user i had logged in that was running VLC and quit VLC.  still saw the kernel_task suckage.  switched back to my regular user and the problem went away.

     

    if the theory that this is related to a buggy AppleHDA.kext is true (which i think likely), will somebody try this possible workaround next time they see the issue and report back?  i'm too lazy to try to see if i can repro the issue easily ;P

    --

    $ sudo kextunload /System/Library/Extensions/AppleHDA.kext

    $ sudo kextload /System/Library/Extensions/AppleHDA.kext

    --

     

    thanks!

    marc

  • by imac2,

    imac2 imac2 Jan 7, 2014 2:17 PM in response to Marc Bejarano
    Level 1 (15 points)
    Jan 7, 2014 2:17 PM in response to Marc Bejarano

    I have a similar problem and thought I would mention it here although this is related to MacBook Air and I am using a MacBook Pro.

     

    Anyway, Kernel_task is using upto 10 GB of my 16 GM Ram when I am trying to save a file from iMovie and then I get the message that the system has run out of application memory. Never had this problem in the older versions of OS and iMovie.

     

    I use Apple TV and Apple Express to stream music, so it may be connected to the sound issue mentioned in the thread.

     

    Any suggestions would be greatly appreciated.

     

    By the way Genius Bar at the local Apple store is telling me I have a hardware issue. But all this started after upgrading to the latest OS etc.

     

    Thanks.

  • by SundanceX,

    SundanceX SundanceX Jan 7, 2014 8:20 PM in response to Marc Bejarano
    Level 1 (5 points)
    Jan 7, 2014 8:20 PM in response to Marc Bejarano

    Marc, you're a genius - this actually fixed it!

     

    $ sudo kextunload /System/Library/Extensions/AppleHDA.kext

    $ sudo kextload /System/Library/Extensions/AppleHDA.kext

     

    CPU went back down to normal levels immediately after that. I would encourage everyone to try this one out.

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