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 erfarw,

    erfarw erfarw Jan 2, 2014 9:12 AM in response to HalexPereira
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    Jan 2, 2014 9:12 AM in response to HalexPereira

    It seems that it only happens when Google Chrome is running. Could someone confirm this?

  • by Mikeruoc,

    Mikeruoc Mikeruoc Jan 2, 2014 9:19 AM in response to erfarw
    Level 1 (0 points)
    Jan 2, 2014 9:19 AM in response to erfarw

    That's what I posted earlier in the tread. Been using safari for the last week and no issues. If I leave chrome open and close the lid wait a minute or 2 and open it I get high kernel_task. Close chrome and close the laptop and wait another minute or 2 and then open the laptop kernel_task drops off. So for me it is chrome.

  • by drewrob26,

    drewrob26 drewrob26 Jan 2, 2014 9:28 AM in response to erfarw
    Level 1 (0 points)
    Jan 2, 2014 9:28 AM in response to erfarw

    I've seen it happen on a stock MacBook so I'm not sure it's chrome.. Mine has been acting up lately while using the microphone, so perhaps google chrome accesses the microphone for some reason?  My computer used to do it with audio output, and now it seems to only do it on input.   I have the most issues after using voice chat in Steam.  Hope this helps!

  • by Mikeruoc,

    Mikeruoc Mikeruoc Jan 2, 2014 9:30 AM in response to drewrob26
    Level 1 (0 points)
    Jan 2, 2014 9:30 AM in response to drewrob26

    Chrome does use the mic. I have the hot word plugin installed. I will try uninstalling it.

  • by contempt1,

    contempt1 contempt1 Jan 2, 2014 9:33 AM in response to HalexPereira
    Level 1 (0 points)
    Jan 2, 2014 9:33 AM in response to HalexPereira

    Unfortunately, I use Firefox and rarely run Chrome and I've been suffering through this. I don't believe it's any one app as you can see from my history, Apple tech blamed it on my Drobo driver to which Drobo claimed it's definitely not. Plus, I'm having a difficult time replicating this bug. Sometimes it happens and other times it doesn't even if I'm performing the exact same task. And sometimes restarting doesn't always fix it whereas other times I could have my computer running for 24 hours and waking from multiple sleeps and the problem isn't replicable. Incredibly frustrating.

  • by erfarw,

    erfarw erfarw Jan 2, 2014 9:35 AM in response to Mikeruoc
    Level 1 (0 points)
    Jan 2, 2014 9:35 AM in response to Mikeruoc

    I don't have Hot Word installed.

    So it seems the problem is related to the sound driver and it happens when Chrome is running.

     

    If someone from the Apple staff is reading this: I'm available for testing and giving more details to help correcting this problem.

  • by erfarw,

    erfarw erfarw Jan 2, 2014 9:39 AM in response to contempt1
    Level 1 (0 points)
    Jan 2, 2014 9:39 AM in response to contempt1

    I can replicate the problem on my Mac:

    1. Open Chrome
    2. Go to sleep
    3. Wait 5 minutes
    4. Wake it up
  • by milo jah,

    milo jah milo jah Jan 2, 2014 9:40 AM in response to erfarw
    Level 1 (10 points)
    Jan 2, 2014 9:40 AM in response to erfarw

    I've had it happen on a fresh 10.9.1 install with no 3rd party apps.

     

    However, I do use Chrome, and I do use hot word. When I disabled hot word, kernel CPU went back to normal.

     

    Then I closed Chrome, waited a minute, and close the laptop (mid-2013 AIR), reopening another minute later and CPU was pegged again...

     

    I've found that if my battery is less than 100%, and I connect the power adapter while close, wait for the magsafe to turn orange and open, it's 50/50 that the CPU will be normal. If I open not connected to the power, it's pegged 100% of the time.

     

    Is there a way to disable the sound driver/hardware (like an rmmod)?

  • by erfarw,

    erfarw erfarw Jan 2, 2014 9:44 AM in response to milo jah
    Level 1 (0 points)
    Jan 2, 2014 9:44 AM in response to milo jah

    OK, some corrections:

     

    I can replicate the problem on my Mac (mid-2013 air, power adapter plugged in):

    1. Open Chrome
    2. Go to sleep
    3. Wait 5 minutes
    4. Wake it up
  • by Mikeruoc,

    Mikeruoc Mikeruoc Jan 2, 2014 9:49 AM in response to erfarw
    Level 1 (0 points)
    Jan 2, 2014 9:49 AM in response to erfarw

    I uninstalled hot word and then tried to recreate it and so far it has not happend. But I will give it a few days and see. It may not be Chome it might be the way an app access the mic or sound driver. So to the person who said they have it and are on Firefox I would look at a plugin or app that is accessing the sound. For me it seems it was the hotword plug in chrome.

  • by joeyjohnson,

    joeyjohnson joeyjohnson Jan 2, 2014 10:53 AM in response to Mikeruoc
    Level 1 (12 points)
    Photos for Mac
    Jan 2, 2014 10:53 AM in response to Mikeruoc

    Sorry everyone, but there is so much junk being discussed here its really wasting everyone's time. Of course Apple have propogated most of the red herrings, such as Drobo stuff above.

     

    I never use Chrome. I have never even heard of Hot Word. I can get this problem with NO APPS RUNNING. Restarting doesn't fix it more than 1 in 3 or 4 tries. I have rebooted 4 times today, and still my machine is running like a dog. Apple don't care, it's as simple as that. Likewise, I don't care much for Apple any more, having been one of their biggest fans in the past.

     

    Mavericks has huge memory leaks, and many bugs they are not addressing for some reason. Maybe they have a contract with the NSA, maybe that's why this "problem" can't be "fixed".

  • by Qual30k,

    Qual30k Qual30k Jan 2, 2014 3:14 PM in response to erfarw
    Level 1 (0 points)
    Jan 2, 2014 3:14 PM in response to erfarw

    Yea my kernel/audio issue occurs with audio in general (Safari, iTunes, w/e) - I haven't tried Chrome.

     

    Blaming the NSA won't solve anything...

  • by bausi,

    bausi bausi Jan 2, 2014 11:43 PM in response to HalexPereira
    Level 1 (10 points)
    Jan 2, 2014 11:43 PM in response to HalexPereira

    still 10.9.1 didn't solve the problem...

     

    very disapointing

  • by erfarw,

    erfarw erfarw Jan 3, 2014 2:38 AM in response to HalexPereira
    Level 1 (0 points)
    Jan 3, 2014 2:38 AM in response to HalexPereira

    Just tested without Chrome and still get the 100% CPU.

    Chrome seems not to be at fault...

  • by Herbygold,

    Herbygold Herbygold Jan 3, 2014 11:41 AM in response to HalexPereira
    Level 1 (0 points)
    Jan 3, 2014 11:41 AM in response to HalexPereira

    ....i have this on several MacBook´s (Air), also on MacBooks of friends. Different configuration. One work around work everyware:

     

    a) start iTunes (or another Audio app)

    b) close MBA

    c) wait 10 sec

    d) open: 100% Task go down

     

    BUT: Apple, please fix it!!!!!!!!!!!

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