kernel_task running wild!

You can kill the process in Activity Monitor click the runaway process, by clicking on it.

Quit

If there are other partitions on the external HD make sure they are in the list to EXCLUDE. See TM>preferences>options

Disable indexing of your external drive by spotlight

and see what happens. Do this in Preferences->Spotlight

and select the privacy button and and add the external

drive to the list to prevent searching reboot and

see what happens.

Also, do you have another drive or a USB stick to plug

in and see if the same thing happens. Forgot to ask,

is it a Firewire or USB drive and what Make/Model.

Same issue after OS X Lion upgrade. I am running 10.7.1... 😠

Other applications

1. Preview in full screen. This is the first app that hung itself when i tried zoom in then zoom out using double finger tap; and then the kernel_task showed 100%.
2. Safari in full screen (it was the next one to hang)
3. Microsoft Word in another desktop

I am running 2.4 GHz Intel Core i5. 4 GB Ram.

No external devices.

Offlate, I've started encountering this issue almost once every 2 days.

(sorry for the duplicate post)

Message was edited by: npunhani

I have had this problem with Lion on my old Mini lately. Don't know what causes it but the system gets VERY laggy to the point of being unuseable. I discovered today that it was the kernel_task going wild. Never ever happened in Snow Leopard for me at least. Anyway, the fix for me was to select the kernel_task in the Activity Monitor and click 'Inspect'. When I did that it immediately went down to <1% CPU activity. I don't know if this is reproducible since I only just discovered it. Much better than having to restart which takes forever anyway with the kernel_task using up 99% of the CPU!

Hi,

I have a new MBA (that came out with OS X Lion) and I've been having this problem too.

I have narrowed down the cause to the "Power Throttle State"

If you open up Console (search for it using spotlight) and view the logs, you'd notice that when the Power Throttle State is 1, the CPU usage is close to 0. When it's 0, then the CPU usage shoots up to 300% or so (for me).

I suppose it changes the Power Throttle State in response to CPU temperature.

Mine's around 50 degrees celsius.

The OS can change the Power Throttle State many times in a minute, as the temperature fluctuates.

I haven't however found a solution except to cool the MBA (even this is inconsistent: I get slow performance even in a cold room)

snow_bunny, this isn't an MBA issue as I am having exactly the same sh-t on my MC374. Trying to get rid of this, I erased my backup disk and had made a new backup, but the same problem emerged when I tried to make next backup, and MBP started to behave weird — applications didn't start, system preferences didn't open. When I tried to stop backing up, system partly freezed (SBOD appeared, TM icon in the system tray freezed, and programs refused to start).

This is the next thing I planned to check — I am pretty sure I had noticed this right after I encrypted my backup a few days ago. I'll let you know if it helps.

And, did your Spotlight reindex disk after reboot?

It seems like the cause is backup encryption; as far as I see, Lion doesn't work right with encrypted volumes — I just rebooted, turned automatic backup off and plugged in my hard drive. Disk Utility failed to unmount it when I tried to erase the volume, name of the partition turned to disk2s2 when I restarted Disk Utility.

Look, was the backup volume the only on your hard drive? I encounter Disk Utility's strange behavior — I erased both partitions on my HDD (400 Gb used for TM and 240 Gb used for data storage), and when I tried to create one partition of 640 Gb named, for example, "Time Machine", it made 400 Gb partition called "disk2s2". What a...

Eventually, everything works fine after I made unencrypted backup.

Ridiculous.

DROPBOX is guilty

just disabling the launch after restart has slow down to almost zero the kernel process.

Having the same problem here. It is not Dropbox, it is not encryption, nor anything else suggested here. I am finding that my bluetooth Magic Trackpad goes insane in terms of latency. I would suggest you file a bug here: bugreport.apple.com with the details of your experiences for more detailed analysis.

The short of it, here, is that it appears that whenever there is very heavy file system activity the kernel_task shoots through the roof (~300-400% each time here) and then system latency likewise goes nuts. It appears to be an IO blocking issue. It also tends to be more likely to occur when you're pushing the upper thresholds of your memory limit.

Running on a Mac Pro 16 core system, 20GB RAM.