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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

sunQH

Level 1

4 points

Oct 30, 2013 10:34 PM in response to HalexPereira

I also have this issue. When I plug-out my earphone, the CPU usage of kernel_task will be normal. I think it must be a bug of Mavericks in 2013 Macbook Air.

Jayk2

Level 1

0 points

Oct 31, 2013 2:02 AM in response to sunQH

Same problem here guys. I was going crazy thinking it was an issue with my MBA but at least it looks like a bug. Apple, when are you guys going to release a fix?

After upgrading to Mavericks whenever I resume my macbook air late 2013 from sleep Kernel_task runs at 100% cpu killing my battery time down to just 6 hours on 100% charge. Nothing seems to fix this problem unless I hard reset the MBA - not good!

More battery life with Mavericks? Seems like mavericks is cutting my MBA's battery life down by 50% to just 6 hours on a full charge :-(

I'm hoping Apple are aware of this issue and working on a fix asap. It's a real shame to see an OS X upgrade kill the MBA's battery life so detrimentally, especially seeing as this is the latest model of their macbook air model from late 2013.

I followed the advice from the previous posts but headphones or no headphones I haven't really noticed any difference. The problem occurs hwether I boot from cold with or without headphones. Once I close the lid on the MBA and resume from sleep Kernel_task runs at 100% cpu and drains the battery to just 6 hours usage on a full charge.

sunQH

Level 1

4 points

Oct 31, 2013 2:08 AM in response to Jayk2

In my situation, when my MBA wakes up with a earphones pluging-in, the kernel_task will take 100% CPU usage. If I plug-out my earphones, the CPU usage will be released.

Could you lanuch the monitor to take a sysdiagnostics in order to find out the certain thread taking the most of the CPU.

Oct 31, 2013 4:03 AM in response to HalexPereira

I have the very same problem on a Macbook Air mid 2011

No headphones connected and not even a restart / shutdown resolves the problem

kernel_task just goes crazy for a couple of hours randomly

Very frustrating, lets hope a fix comes quickly...

XaverCZE

Level 1

0 points

Oct 31, 2013 4:55 AM in response to HalexPereira

I have the same problem. When my MBA wake up, I have sometime kernel_task about 25-30% of CPU load. Its crazy but only restart help me. I have clean install of Mavericks and only iWork, iLife, Flash and VLC installed. Thats all. When I restart my MBA my battery indicates about 14-15 hours of battery life. When I put MBA into a sleeping mode, so kernel_task rapidly increases to 30% of CPU usage and battery shows about 6 hours. I think that the ML is the right way in this time. Mavericks is full of bugs.

XaverCZE

Level 1

0 points

Oct 31, 2013 5:13 AM in response to XaverCZE

I just found out that it causes a running video. Here is a how to bug kernel_task. Run a some video and put your Mac to sleep mode. When they wake up, you have kernel_task bugged now. Maybe it causes running audio too. Its unbelievable and I installing ML now.

Oct 31, 2013 5:20 AM in response to XaverCZE

Does installing ML fix it? Or better still reverting to a previous ML install via time Machine?

Oct 31, 2013 6:51 AM in response to Andy_Kenney

From my system Diagnostics Powermetics.txt file - Doesn't seem to be HDEF on my machine...

**** Session Interrupt distribution ****

CPU 0:

Vector 0x46(SMC): 0.04 interrupts/sec

Vector 0x49(MacBookAir4,1): 7.22 interrupts/sec

Vector 0x56(HDEF/EHC1): 0.13 interrupts/sec

Vector 0x57(EHC2): 26.25 interrupts/sec

Vector 0x90(IGPU): 8.30 interrupts/sec

Vector 0x91(HDEF): 2.66 interrupts/sec

Vector 0x92(pci8086,1c3a): 0.24 interrupts/sec

Vector 0x93(SATA): 67.88 interrupts/sec

Vector 0x94(ARPT): 15.35 interrupts/sec

Vector 0x95(NHI0): 1.45 interrupts/sec

Vector 0xdd(TMR): 581.46 interrupts/sec

Vector 0xde(IPI): 161.07 interrupts/sec

CPU 1:

Vector 0xdd(TMR): 119.81 interrupts/sec

Vector 0xde(IPI): 1328.86 interrupts/sec

CPU 2:

Vector 0xdd(TMR): 129.41 interrupts/sec

Vector 0xde(IPI): 192.00 interrupts/sec

CPU 3:

Vector 0xdd(TMR): 91.36 interrupts/sec

Vector 0xde(IPI): 1369.68 interrupts/sec

Jayk2

Level 1

0 points

Oct 31, 2013 10:28 AM in response to XaverCZE

No replicable symptoms here. Kernal_task will run at 100% CPU usage and kill the battery down to 6 hours on a full charge regardless of whether I have headphones, no headphones, movie or no movie playing. After the MBA 2013 resumes from sleep (usually after a few times) Kernel_task shoots up to 100% CPU usage and stays there constantly. Seriously considering going back to ML :-(

XaverCZE

Level 1

0 points

Oct 31, 2013 10:54 AM in response to Jayk2

Yes, happened to me without video playback right now. Its probably bug of Mavericks and its due to sleeping mode. Definitely coming back now, it's necessary. I am frustrated of this. Apple Apple, what you doing ... ?

mdxico

Level 1

0 points

Oct 31, 2013 7:07 PM in response to HalexPereira

Hi, here is the same. I have published a post on my blog (pt-br) http://andrei.rosseti.eti.br/2013/10/kernel_task-utilizando-100-de-cpu-no-os-x-m avericks-10-9/ with a short video explaning when it happens.

Apple, please, correct this issue sooner. 😉

Thank you.

Oct 31, 2013 8:14 PM in response to sunQH

Same situation. Its effed up. I dont listen to music anymore on the move to maintain my battery life. Apple please do something about this

Nov 1, 2013 2:07 AM in response to Andy_Kenney

Just chatted with a support guy - Who was very helpfull.

His suggestion for my Mid 2011 Mackbook Air was to do a clean re-install of Mavericks by booting the the recovery drive (holding down the option key when booting) - Wasn't keen on doing a full back-up whilst Kernel_Task was killing my machine...

What I did notice was that just booting to the revovery drive and then re-starting gets my fans and Kernel_Task back under control, where a standard re-boot / full re-set and anything else just keeps Kerenl_Task going crazy...

Not sure I'll do a clean install just yet - As long as I can make it go away when it happens, I'll feel better when the first Mavericks patch comes...

uvesten

Level 1

0 points

Nov 1, 2013 3:09 AM in response to HalexPereira

Same here, kernel_task sometimes goes crazy upon waking from sleep. MBP 17-inch, Early 2011.

Roy So

Level 1

0 points

Nov 2, 2013 10:00 AM in response to HalexPereira

Same here on my new MacBook Pro Retina 13 inch 2013.

Apple should do something to this problem.

kernel_task is using 100% CPU when waking from sleep