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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

Nov 5, 2013 2:56 PM in response to HalexPereira

I have the same problem with a Mid 2013 MacBook Air 11inch.

With Battery not really usable, no support because more than 90 days old.....

It is a shame Apple!!!

Nov 5, 2013 3:36 PM in response to Jan Teurlings

So I'm just wondering, does everyone here use VLC?

I've updated VLC from 2.0.8 to 2.1.0 and haven't seen the issue occur again. They don't directly say what type of bug fixes have been made, but they do say that A LOT (~1000) were fixed in the new release. Also, a rewritten audio core.

https://www.videolan.org/vlc/releases/2.0.8.html

https://www.videolan.org/vlc/releases/2.1.0.html

Changelog here:

https://www.videolan.org/developers/vlc-branch/NEWS

It's been maybe 5-6 days without seeing the kernel_task issue, alternating between headphones and not and sleep etc (no reboots). Might be too early to tell though..

I'm thinking it could be a two part problem:

- issue in the audio driver (HDEF/AppleHDA.kext)

- issue in how an application engages the audio driver (VLC, iTunes maybe?)

All of this aside, the kernel_task and system CPU usage in Mavericks does seem to be pretty chatty and in excess compared to Mountain Lion.

TLDR; I suspect there will be numerous fixes in the next update, which I hope comes sooner than later 🙂

Nov 5, 2013 6:32 PM in response to HalexPereira

Having the same issue.

Latest Macbook Pro Retina 13" release.

Also due to headphone (using pioneer DJ headphones) and running logic.

A fix would be great!

Nov 5, 2013 6:37 PM in response to HalexPereira

So is this a hardware or software issue?

Nov 5, 2013 6:42 PM in response to crazyhakins1

It's not hardware, problem goes away when reverting to Mountain Lion.

Nov 6, 2013 1:56 PM in response to espressodre

UPDATE: This issue is happening for me whether I have headphones plugged in or not. regularly having to restart my macbook, and wondering if this is going to reduce the life of my machine with the CPU regularly working so hard.

Nov 6, 2013 1:57 PM in response to Herbygold

I still have my 90 days of support... might give them a call!

Nov 6, 2013 5:45 PM in response to HalexPereira

POSSIBLE FIX:

I found a fix for this problem on my mid-2013 MacBook Air. It's been draining my battery so i used the program memory clean and after clearing my RAM the "kernal_task" useage went down. Hope this helps.

https://itunes.apple.com/ca/app/memory-clean/id451444120

Can you please test it to see if it works for you?

xtux

Level 1

0 points

Nov 7, 2013 12:15 PM in response to HalexPereira

I am having the same issue on my new MacBook Pro 13'' Retina Display. (Late 2013).

I've been using the following workarrounds:

1. Unplugg Earphones

2. Restart

I've also changed my MacBook Pro with a new one today( MacBook Pro 13'' Retina Display, 8Gb Ram, 500 HDD) fresh setup, still the issue is there.

I also do have an MacBook Air 2012 -> No problems here.

Opened 3 Tickets @ Apple Support:

1. Ticket 1 & 2: Told me it could be a hardware issue or software, and I should change it with a new one. I did. Still the problem is there.

2. Ticket 3: Looked over Tickets history it seems they got some tickets/feedbacks regarding Kernal Task Process issues.

Most probably it will be fixed in an update.

PS: ' At the APPLE Store I've also tried it on different Late 2013 MBP and MBA. Same issue.

erickw

Level 1

0 points

Nov 7, 2013 5:27 PM in response to HalexPereira

Just experienced this problem on recent MBA 13" with Mavericks. I haven't plugged in any earphones in some time, but it looks like it started happening quite soon after wake from lid close (I didn't notice until the fan started running about half an hour later.)

The 100% cpu usage seems to be coincident with a log file /var/log/gaudit.log being extremely active (about 15 log events per second on average!)

erickw

Level 1

0 points

Nov 7, 2013 5:53 PM in response to erickw

Follow-up: here's my interrupt distribution from sysdiagnose:

**** Interrupt distribution ****

CPU 0:

Vector 0x49(MacBookAir6,2): 61.53 interrupts/sec

Vector 0x92(IGPU): 897.08 interrupts/sec

Vector 0x94(XHC1): 0.99 interrupts/sec

Vector 0x96(HDEF): 223546.36 interrupts/sec

Vector 0x98(ARPT): 82.36 interrupts/sec

Vector 0x9e(SSD0): 0.99 interrupts/sec

Vector 0xdd(TMR): 424.72 interrupts/sec

Vector 0xde(IPI): 757.16 interrupts/sec

CPU 1:

Vector 0xdd(TMR): 195.49 interrupts/sec

Vector 0xde(IPI): 1140.20 interrupts/sec

CPU 2:

Vector 0xdd(TMR): 623.19 interrupts/sec

Vector 0xde(IPI): 4156.93 interrupts/sec

CPU 3:

Vector 0xdd(TMR): 350.30 interrupts/sec

Vector 0xde(IPI): 2054.15 interrupts/sec

Nov 8, 2013 5:32 AM in response to Cannonfodda

OK I tried Cannofodda's tip and it seems to work. I do have to unplug the earphones first though, otherwise Memory Clean does not work. It's not really a fix but a good work around for the moment.

Jan

HalexPereira Author

Level 1

7 points

Nov 8, 2013 6:08 AM in response to Jan Teurlings

It's been a while since the last time kernel_task ran wild here, but I've been keeping my eyes peeled and Activity Monitor running around the clock. This is definitely NOT ideal.

There are some pretty awesome workarounds for this issue, here. Thanks to everyone who contribbuted! However, it's important we find some way to fix the problem in the source. Workarounds shouldn't be our goal, there should be a definite solution to this. Preferably, something that doesn't require risking damaging the OS.

Maybe we could use the feedback section on Apple.com and point them to this thread? Or even boost the signal, so more people can add to the discussion.

mdburch

Level 1

0 points

Nov 8, 2013 7:49 AM in response to HalexPereira

On my mid-2013 MacBook Air running OSX 10.9 Mavericks, I had the same problem with kernal_task running at over 100% of CPU after waking from sleep. I had installed Boom, a speaker booster, which worked fine under 10.8. Once I removed Boom the problem went away.

Dalaen

Level 1

4 points

Nov 11, 2013 4:31 AM in response to HalexPereira

I have similar issue.

I have no exotic software installed. Dropbox & Spotify I would say.

My kernel_task is using a whole thread (25% CPU on my dual-core rMBP) when the earphones are plugged in.

Just unplugging them will drop the charge led by kernel_task almost instantly.

Would be nice if Apple acknowledged this bug. Has anyone reported it yet successfully to them?

kernel_task is using 100% CPU when waking from sleep