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HalexPereira Author

Level 1

7 points

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

323 replies

John_Raz

Level 1

0 points

Jan 8, 2014 12:51 AM in response to HalexPereira

If you want to fix the problem on MacBook Air and MacBookPro waiting to Apple to release a new AppleHDA driver, use the method i have describe:

https://discussions.apple.com/thread/5497235?answerId=24178943022#24178943022

srodal

Level 1

0 points

Jan 8, 2014 1:01 AM in response to John_Raz

I'm not sure I understand, you say you "use the AppleHDA from 10.8.5". Well, I am already running 10.8.5 and I still have the problem occasionally. How would it help to install the driver from 10.8.5 when I'm already running 10.8.5?

John_Raz

Level 1

0 points

Jan 8, 2014 1:24 AM in response to srodal

I speak about the specific problem on MBA and MBP with AppleHDA driver of mavericks 10.9.0 and 10.9.1, with cpu goes to 100% when using an audio application (with headphone plug in) and the computer go to sleep then wake up.

srodal

Level 1

0 points

Jan 8, 2014 1:32 AM in response to John_Raz

My issue is different but with similar symptoms then, when it happens the CPU usage of kernel_task goes to more than 300 %. Sometimes after restarting a couple of times it stops happening for a while.

cyclix86

Level 1

4 points

Jan 8, 2014 6:51 AM in response to Marc Bejarano

Unloading and reloading the AppleHDA.kext kernel extension as described above did nothing for me. kernel_task still using ~100% CPU on the primary core after wake from sleep. I'm on the lastest Mavericks (10.9.1) on a new 2013 Retina MacBook Pro 13".

gattol

Level 1

0 points

Jan 8, 2014 6:57 AM in response to cyclix86

Same here.

Jan 8, 2014 8:16 AM in response to gattol

With me unloading the AppleHDA.kext did drop CPU usage but I did get an error message:

(kernel) Can't unload kext com.apple.driver.AppleHDA; classes have instances:

(kernel) Kext com.apple.driver.AppleHDA class AppleHDAWidgetCS4208 has 8 instances.

(kernel) Kext com.apple.driver.AppleHDA class AppleHDAEngine has 2 instances.

(kernel) Kext com.apple.driver.AppleHDA class AppleHDAEngineOutput has 2 instances.

(kernel) Kext com.apple.driver.AppleHDA class AppleHDAEngineOutputDP has 1 instance.

(kernel) Kext com.apple.driver.AppleHDA class AppleHDAEngineInput has 1 instance.

(kernel) Kext com.apple.driver.AppleHDA class AppleHDAStream has 2 instances.

(kernel) Kext com.apple.driver.AppleHDA class AppleHDAPath has 5 instances.

(kernel) Kext com.apple.driver.AppleHDA class AppleHDAWidget has 2 instances.

(kernel) Kext com.apple.driver.AppleHDA class AppleHDANode has 1 instance.

(kernel) Kext com.apple.driver.AppleHDA class AppleHDAPathSet has 5 instances.

(kernel) Kext com.apple.driver.AppleHDA class AppleHDAPathControl has 8 instances.

(kernel) Kext com.apple.driver.AppleHDA class AppleHDAWidget_80862807 has 2 instances.

Failed to unload com.apple.driver.AppleHDA - (libkern/kext) kext is in use or retained (cannot unload).

Reloading afterwards worked but I had lost all sound. Only a restart could fix it.

antony-m

Level 1

0 points

Jan 8, 2014 9:05 AM in response to Jan Teurlings

You can run it with -c flag such as this:

sudo kextunload -c /System/Library/Extensions/AppleHDA.kext

It will terminate all those instances. This fix didn't work for me though.

Jan 8, 2014 3:59 PM in response to HalexPereira

Problem goes away when I unplug my headphones that have a control.

Jan 9, 2014 3:54 AM in response to antony-m

For the record: kextunload without '-c' fixes the problem for me (late 2013 Retina MacBook Pro 13") with the know problem of losing the sound, using the '-c' option does not help.

I hope there will be a final solution soon.

John_Raz

Level 1

0 points

Jan 9, 2014 4:34 AM in response to HalexPereira

Why are you trying to use non working solution like trying to unload a driver instead of replacing the default driver with one that work like i describe here: https://discussions.apple.com/thread/5497235?answerId=24178943022#24178943022 ?

Jan 9, 2014 5:38 AM in response to John_Raz

Because someone answered your post with the statement, that the solution does not work on late 2013 MBPs

bausi

Level 1

23 points

Jan 9, 2014 6:29 AM in response to John_Raz

seems to work for me!

gattol

Level 1

0 points

Jan 9, 2014 6:48 AM in response to bausi

On late 2013 mbp retina?

Joelem

Level 1

0 points

Jan 9, 2014 7:55 AM in response to HalexPereira

I had a similar problem where my fans would go crazy and the spinning beach ball of death would appear every 5 seconds rendering even simple computer usage null. I ended up removing the soundflower.kext (I'm guessing audio hijack pro or audacity installed that): /System/Library/Extensions/Soundflower.kext

Everything has been back to normal since then.

kernel_task is using 100% CPU when waking from sleep