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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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323 replies

Oct 28, 2013 4:07 PM in response to HalexPereira

I'm in the same boat. No issues before installing Mavericks.


I did the same tests, even disabled the 3rd party kext I had (pace driver, related to some vst plugins I have) with no luck.


I ran sysdiagnostics and can see the following interrupts, taken from powermetrics.txt:


**** Interrupt distribution ****



CPU 0:

Vector 0x49(MacBookAir6,2): 31.67 interrupts/sec

Vector 0x92(IGPU): 408.07 interrupts/sec

Vector 0x96(HDEF): 216491.54 interrupts/sec

Vector 0x98(ARPT): 11.06 interrupts/sec

Vector 0x9e(SSD0): 25.10 interrupts/sec

Vector 0xdd(TMR): 367.54 interrupts/sec

Vector 0xde(IPI): 161.86 interrupts/sec

CPU 1:

Vector 0xdd(TMR): 32.17 interrupts/sec

Vector 0xde(IPI): 56.18 interrupts/sec

CPU 2:

Vector 0xdd(TMR): 934.68 interrupts/sec

Vector 0xde(IPI): 1103.50 interrupts/sec

CPU 3:

Vector 0xdd(TMR): 165.04 interrupts/sec

Vector 0xde(IPI): 242.83 interrupts/sec



I feel like that is not normal(see bold) 🙂 Anyone know what HDEF is referring to, might help tracking this down.

Oct 28, 2013 9:36 PM in response to HalexPereira

Hi guys. I was experiencing exactly the same issue, after sleep kernel_task always used 100% cpu. While reading HalexPereira post I realized I was using earphones! I recreated the problem and then fixed it just unplugging the earphones, closing the lid and opening it again... The problem must be related with AppleHDA for sure...

Oct 29, 2013 3:12 AM in response to HalexPereira

One more thing that would confirm that something is wrong with the HDA driver - today the sound stopped working without any apparent reason. The audio enable/disable and volume keys on the keyboard show a greyed out HUD on the screen. But the kernel_task issue on wake up is gone!!! Now I think I'm not gonna restart it, hehe I prefer it without sound and without kernel_task lol.

Oct 29, 2013 1:47 PM in response to HalexPereira

I have the same issue happening, kernel_task ramps to 100% and only a restart will fix it. Seems to only happen after my MBA (mid-13) has had teh lid down and comes back from sleep.


I do use headphones but I have not nailed it done to that fully. I am also getting an issue where sound will competly stop if the system goes into deep sleep.

praying for a fix soon...very very annoying.

Oct 29, 2013 10:44 PM in response to HalexPereira

I have the same issue. But for me, the weird thing is. It happens only when I keep my headphones plugged in. WHen i remove my headphones, it stabilizes i.e Kernel_task goes back to using just 4-5% CPU. I resetted PRAM SMC etc but to no avail. Now I dont feel like using my headphones a lot because of this when I am travelling because battery life reduces to 6 hours

Oct 30, 2013 7:33 AM in response to HalexPereira

Exact same problem for me. And I unplug the headphone, sleep, then wake up, it's gone!

I really hope apple can solve this quickly.


**** Interrupt distribution ****



CPU 0:

Vector 0x92(IGPU): 1241.09 interrupts/sec

Vector 0x94(XHC1): 71.54 interrupts/sec

Vector 0x96(HDEF): 216026.79 interrupts/sec

Vector 0x98(ARPT): 20.87 interrupts/sec

Vector 0xdd(TMR): 460.07 interrupts/sec

Vector 0xde(IPI): 469.01 interrupts/sec

CPU 1:

Vector 0xdd(TMR): 60.61 interrupts/sec

Vector 0xde(IPI): 227.55 interrupts/sec

CPU 2:

Vector 0xdd(TMR): 372.63 interrupts/sec

Vector 0xde(IPI): 1658.43 interrupts/sec

CPU 3:

Vector 0xdd(TMR): 185.82 interrupts/sec

Vector 0xde(IPI): 763.14 interrupts/sec

kernel_task is using 100% CPU when waking from sleep

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