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 kuerbiskopf,

    kuerbiskopf kuerbiskopf Jan 11, 2014 4:05 AM in response to Teddyph33r
    Level 1 (2 points)
    Jan 11, 2014 4:05 AM in response to Teddyph33r

    I don't have flash and have the exact same symptoms. (though a have Chrome which I almost never use, with has flash but sandboxed)

  • by Richard Heppner, Jr.,

    Richard Heppner, Jr. Richard Heppner, Jr. Jan 11, 2014 7:42 AM in response to HalexPereira
    Level 1 (65 points)
    Jan 11, 2014 7:42 AM in response to HalexPereira

    I'm experiencing the same issue on a late 2013 rMBP (I don't use headphones or Chrome). 

     

    I have MenuMeters installed, which monitors CPU usage.  For what it's worth, it shows that the over 100% usage is happening on only one of the processors.

  • by steveb52,

    steveb52 steveb52 Jan 11, 2014 9:54 AM in response to HalexPereira
    Level 1 (0 points)
    Jan 11, 2014 9:54 AM in response to HalexPereira

    I began experiencing this problem after having my MBP 8,2 (early 2011, OS 10.9.1) battery replaced.

     

    I suspect that there is a relationship.

     

    Found a temporary solution that works very well for this symptom, but concerns me as to its long-term impact on the system.  You can find it by searching for "Fixing kernal_task CPU Problems."  The solution involves removing the plist that manages power, fans, etc., which makes it quite scary.  However, my system is unusable without the fix.

     

    We need a permanent solution.

     

    This seems to impact laptops exclusively - which points towards the battery.  Of course it could be other things, but I have not seen any iMacs having this problem in my fairly wide-ranging search of forums.

     

    Apple, please help!

  • by milo jah,

    milo jah milo jah Jan 11, 2014 9:57 AM in response to Richard Heppner, Jr.
    Level 1 (10 points)
    Jan 11, 2014 9:57 AM in response to Richard Heppner, Jr.

    Using "Activity Monitor", it is always the top CPU graph that goes to 100%. Does anybody know if that is always the same core (I assume core0), and if OSX always has kernel affinity to that core?

     

    ---

     

    I have received one set of diagnostics files, and have attached them to the bug report I have open for this. Please consider sending your own diag files so I can attach more. The more data we can provide Apple, the quicker they can fix this. Additionally, it makes it less likely that the ticket will be closed due to a 3rd party item, if they have samples from a bunch of systems with different configs.

     

    The bug report is # 15724482

    I promise to post any updates to this thread as I receive them.

  • by joeyjohnson,

    joeyjohnson joeyjohnson Jan 11, 2014 11:23 AM in response to milo jah
    Level 1 (12 points)
    Photos for Mac
    Jan 11, 2014 11:23 AM in response to milo jah

    "This seems to impact laptops exclusively - which points towards the battery.  Of course it could be other things, but I have not seen any iMacs having this problem in my fairly wide-ranging search of forums." - GEEEEEEEEEZ!! I am at my wits end. I must have posted on every page that this is NOT just a laptop problem, it happens to my DESKTOP iMac and my friend's too. It is NOTHING to do with batteries, OR headphone cables, OR any of the software programs mentioned in the many pages on this thread. There is only ONE common denominator - APPLE OS on APPLE HARDWARE!

     

    Milo - excellent thanks, I will do likewise. Look forward to any updates, except the one they usually give where they find something unique to your system and blame it on that, if it's 3rd party of course!! As you say, the more the merrier, and the less chance of diversionary tricks!

  • by northwest291,

    northwest291 northwest291 Jan 12, 2014 11:15 AM in response to HalexPereira
    Level 1 (5 points)
    Jan 12, 2014 11:15 AM in response to HalexPereira

    Ok, I discovered something new today.

     

    Earlier, when I had the headphones connected to mt MBPr, the kernel task would go up to 100% when woken up from sleep. Today i found out that the kernel process is ok and idleing IF I have VLC running in the background. I watched a movie and fell asleep today, and woke up when the movie had finished and the mac gone to sleep. When I woke it the kernel was ok. Weird.

     

    I tried to do this  couple of more times, and the same result happened.

  • by Teddyph33r,

    Teddyph33r Teddyph33r Jan 12, 2014 11:18 AM in response to northwest291
    Level 1 (0 points)
    Jan 12, 2014 11:18 AM in response to northwest291

    did you have headphones connected when woken up from sleep with VLC running in the background and CPU was normal?

  • by northwest291,

    northwest291 northwest291 Jan 12, 2014 12:09 PM in response to Teddyph33r
    Level 1 (5 points)
    Jan 12, 2014 12:09 PM in response to Teddyph33r

    Yes!

  • by gattol,

    gattol gattol Jan 13, 2014 6:21 AM in response to HalexPereira
    Level 1 (0 points)
    Jan 13, 2014 6:21 AM in response to HalexPereira

    Can the problem be related to Perian? How many of us has it installed?

  • by neuroman_cer,

    neuroman_cer neuroman_cer Jan 13, 2014 6:29 AM in response to gattol
    Level 1 (0 points)
    Jan 13, 2014 6:29 AM in response to gattol

    I had it installed, but uninstalled it because actually nobody needs perian when you have VLC...

  • by milo jah,

    milo jah milo jah Jan 13, 2014 6:36 AM in response to neuroman_cer
    Level 1 (10 points)
    Jan 13, 2014 6:36 AM in response to neuroman_cer

    Over the weekend, I backed up my Air, and then did a USB reinstall of 10.9. I then looked for a way to reproduce the problem with no 3rd party software.

     

     

    What I found was a way to reproduce the problem 100% of the time.

     

    Go to Settings -> Sound -> input and change the microphone input slider. You should be able to make noise and have the little blue input level dots flash. Then close the lid. Wait 60 seconds and viola, kernel_task at 100% of cpu0.

  • by joeyjohnson,

    joeyjohnson joeyjohnson Jan 13, 2014 6:42 AM in response to milo jah
    Level 1 (12 points)
    Photos for Mac
    Jan 13, 2014 6:42 AM in response to milo jah

    I can reproduce it 100% of the time too. All I have to do is turn my machine on and use it in any way at all for 30-60 minutes. Voila also

     

    I wish there was a button to stay subscribed to this thread but not get any notifications until a solution is found!!!!

  • by CyberWarriors,

    CyberWarriors CyberWarriors Jan 13, 2014 7:09 AM in response to milo jah
    Level 1 (0 points)
    Jan 13, 2014 7:09 AM in response to milo jah

    Wow that shocked me, I'm able to reproduce the problem by using your method shown here. Possible the new chip placed on this latest MBA  is the culprit.

     

    Anyone else who can clarify by using milo jah method, we need to prove this to Apple asap.

  • by joeyjohnson,

    joeyjohnson joeyjohnson Jan 13, 2014 7:11 AM in response to CyberWarriors
    Level 1 (12 points)
    Photos for Mac
    Jan 13, 2014 7:11 AM in response to CyberWarriors

    "Possible the new chip placed on this latest MBA  is the culprit" - how does that explain same symptoms on various other hardware?

  • by CyberWarriors,

    CyberWarriors CyberWarriors Jan 13, 2014 7:17 AM in response to joeyjohnson
    Level 1 (0 points)
    Jan 13, 2014 7:17 AM in response to joeyjohnson

    Well that is based on what we've found, maybe one of it. We don't have enough data to summrize this issues. That why I asking all MBA user to try this method whether they can reproduce the problem or not.

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