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 Dalaen,

    Dalaen Dalaen Nov 11, 2013 4:31 AM in response to HalexPereira
    Level 1 (0 points)
    Nov 11, 2013 4:31 AM in response to HalexPereira

    I have similar issue.

     

    I have no exotic software installed. Dropbox & Spotify I would say.

     

    My kernel_task is using a whole thread (25% CPU on my dual-core rMBP) when the earphones are plugged in.

    Just unplugging them will drop the charge led by kernel_task almost instantly.

     

    Would be nice if Apple acknowledged this bug. Has anyone reported it yet successfully to them?

  • by clostridium,

    clostridium clostridium Nov 11, 2013 8:10 AM in response to xtux
    Level 1 (0 points)
    Nov 11, 2013 8:10 AM in response to xtux

    It is interesting that it was happening on computers in the Apple Store - before that piece of information there was some indication that it may be due to software installed after purchase based on some other threads I've been following. 

     

    I haven't been able to find a pattern yet in my issues but they seem to temporarily go away with a restart like others have noted.  I don't use headphones at all and don't regularly use VLC either and I'm still having this problem so it isn't just connected with either of those issues.  The only thing I've used recently that uses audio is watching Netflix which uses Silverlight. 

     

    It definitely has to destroy battery life.  I run istat menus and have it show the processor temp and CPU power consumption and the thing "idles" at > 10 W when this issue is there and around 1-5 W right now as I type after a reboot.

  • by SI x TRiCKs,

    SI x TRiCKs SI x TRiCKs Nov 12, 2013 10:01 AM in response to HalexPereira
    Level 1 (0 points)
    Nov 12, 2013 10:01 AM in response to HalexPereira

    Hey guys,

    im having the same issue here and also haven't been able to find a pattern. Did someone already contact the genius bar about this? Cause if this issue is not present on all MBPs im definitely going to try to get a new one from the geniusbar. Btw i have installed VLC and i have also used the headphones, but I doubt there is a connection.

  • by Jayk2,

    Jayk2 Jayk2 Nov 12, 2013 11:43 AM in response to SI x TRiCKs
    Level 1 (0 points)
    Nov 12, 2013 11:43 AM in response to SI x TRiCKs

    I went back to ML, it's the only I could solve this issue until Apple release an update.

  • by mdburch,

    mdburch mdburch Nov 12, 2013 11:48 AM in response to Jayk2
    Level 1 (0 points)
    Nov 12, 2013 11:48 AM in response to Jayk2

    Seems like the most common scenario is kernal_task chewing up CPU after MB awakes from sleep.  If you have any apps that use any form of audio, start there.  It was Boom, a speaker booster, that caused the problem for me.  Once I removed it, no problem.  Seems like 10.9 does something different with some audio driver and if an app has not been updated for 10.9, you may have CPU issues.

  • by IE_Armand,

    IE_Armand IE_Armand Nov 12, 2013 11:50 AM in response to HalexPereira
    Level 1 (5 points)
    Nov 12, 2013 11:50 AM in response to HalexPereira

    I don have any additional audio apps installed but still have that issue.

  • by SI x TRiCKs,

    SI x TRiCKs SI x TRiCKs Nov 12, 2013 1:52 PM in response to HalexPereira
    Level 1 (0 points)
    Nov 12, 2013 1:52 PM in response to HalexPereira

    http://support.apple.com/kb/HT3964?viewlocale=en_US&locale=en_US

     

    Spoke to a tech guy who offered me this solution. So far it seems to have worked.

  • by iterva,

    iterva iterva Nov 15, 2013 7:26 AM in response to SI x TRiCKs
    Level 1 (0 points)
    Nov 15, 2013 7:26 AM in response to SI x TRiCKs

    SMC reset has not made a bit of difference for me.

    Kernel_task goes up to 90-100% for me, and stays there until i unplug the headphones and shut the lid to put the mba in sleep mode, then re-open the lid, and plug in the headphones once again.

    This "solved" the issue maybe 7 times out of 10...Only other option left was to reboot the mba.

     

    Installed apps Spotify, Dropbox, Google Drive, Chrome, VLC and iWork.

     

    Ended up reverting back to ML just b/c this was getting way too frustrating... Hopefully this gets resolved soon.

  • by Scott98981,

    Scott98981 Scott98981 Nov 15, 2013 10:22 PM in response to HalexPereira
    Level 1 (8 points)
    Windows Software
    Nov 15, 2013 10:22 PM in response to HalexPereira

    I have the same bug on my brand new late 2013 MBP with retina 13". This only occurs when using iTunes with (Apple) headphones plugged in. Putting the machine to sleep and removing the headphones fixes the problem for at least a short while. Haven't tried doing an SMC reset yet.

  • by pukao,

    pukao pukao Nov 16, 2013 1:08 AM in response to iterva
    Level 1 (0 points)
    Nov 16, 2013 1:08 AM in response to iterva

    I might have a related problem here, CPU usage of the kernel_thread is at 100% after a wakeup. What is possible different with some of you, I don't have this issue after every wakeup but I couldn't narrow it down.

    Reading over this thread I noticed it might related to audio and a lot of you have also Spotify installed. This is also true in my case and after some tests I can reproduce the kernel_thread issue.

    When Spotify plays music while I trigger the standby the kernel_thread goes amok after the wakeup. So at least in my case I can work around this by stopping Spotify playback before going to standby mode.

  • by mhroth,

    mhroth mhroth Nov 16, 2013 3:38 PM in response to pukao
    Level 1 (0 points)
    Nov 16, 2013 3:38 PM in response to pukao

    I have this problem too a new (late 2013) MBP 13" Retina. After closing the lid on the machine and then opening it later, kernel_task is at 100%.

     

    A workaround seems to be to start iTunes and quit it again. This lends some weight to the idea that something in the audio subsystem is causing the problem. Hope this helps.

  • by daveuk82,

    daveuk82 daveuk82 Nov 16, 2013 5:43 PM in response to HalexPereira
    Level 1 (0 points)
    Nov 16, 2013 5:43 PM in response to HalexPereira

    how would u go about reverting back to ml

  • by bausi,

    bausi bausi Nov 18, 2013 11:48 PM in response to mhroth
    Level 1 (10 points)
    Nov 18, 2013 11:48 PM in response to mhroth

    that's cool - it worked for me! maybe the problem came with the latest itunes?

     

    to be sure I also unplugged the jack from the headphones.

     

    br.kg

  • by kawauso,

    kawauso kawauso Nov 19, 2013 5:00 PM in response to HalexPereira
    Level 1 (0 points)
    Nov 19, 2013 5:00 PM in response to HalexPereira

    I've got the same issue with MBP 13" Retina Late 2013, which iTunes nor headphone jack didn't help.

    Recently Apple released 10.9.1 pre-release for developers and that fixed my problem.

    FYI.

  • by Xpis7os,

    Xpis7os Xpis7os Nov 20, 2013 5:33 AM in response to HalexPereira
    Level 1 (0 points)
    Nov 20, 2013 5:33 AM in response to HalexPereira

    HELP - HELP - HELP

    I have MBAir 13" and problem with kernel_task CPU 100%

    I have tried all solutions written here BUT NO SOLUTION. I have restated, plug unplug headphones, open closed iTunes, put to sleep and wake up, done everything and still the problem exists.

    I am using my mini iPad to ask for help as my MBAir is not functioning.

    First time in Apple history an upgrade is so "Microsoft problem like". Apple guys where are you !!!!

    Please help.

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