CPU rising to 100% with Thunderbolt Monitor

[alex s]

Hello,

I'm using:

Macbook Pro - 2011 - 17" - 2.33Ghz i7

Pro Tools 10.3.5 (HD) on Lion 10.7.5

Pro Tools 10.3.6 (HD) on Lion 10.8

Dell 27" monitor with DVI to Thunderbolt adaptor cable.

When I run various sessions, generally sitting at 20% CPU usage,after a minute or so the CPU starts to rise - in a pulsing manner ie. 21/20/23/21/24/22/25/22/27/25/30 all the way up to 100%.

This happens on both Lion and Mountain Lion which I've got on separate partitions.

WhenI unplug the thunderbolt connection to the monitor and reboot Pro Tools all is fine.

Anyone have any ideas ?

Thanks,

Al

[Focuret]

Originally Posted by alex s

Hello,

I'm using:

Macbook Pro - 2011 - 17" - 2.33Ghz i7

Pro Tools 10.3.5 (HD) on Lion 10.7.5

Pro Tools 10.3.6 (HD) on Lion 10.8

Dell 27" monitor with DVI to Thunderbolt adaptor cable.

When I run various sessions, generally sitting at 20% CPU usage,after a minute or so the CPU starts to rise - in a pulsing manner ie. 21/20/23/21/24/22/25/22/27/25/30 all the way up to 100%.

This happens on both Lion and Mountain Lion which I've got on separate partitions.

WhenI unplug the thunderbolt connection to the monitor and reboot Pro Tools all is fine.

Anyone have any ideas ?

Thanks,

Al

You are me. The same thing. Kernel_task starts eating all of the CPU. It's a known problem that when an external monitor is connecte via Thunderbolt kernel_task freaks out.

I solved it for an entire day just by standing the laptop up on it's front where the sleep light is, so that the Apple logo is facing down.

I thought it was a miracle but it came back again today. Try it though, maybe it'll work for you.

The kernel_task losing its [bleep][bleep][bleep][bleep] and hogging all of the CPU is a "feature" that keeps the processor cool. When the computer starts getting too hot it will start looping a random small process over and over again with the highest priority in a bid to cool the system down. It's [bleep][bleep][bleep][bleep]ing retarded because it renders the laptop completely useless but there's a work around.

That throttling is controlled by a file. You can rename this file (don't delete it, you may have to put it back later if it does start overheating and shutting down) and kernel_task won't be an [bleep][bleep][bleep][bleep][bleep][bleep][bleep] anymore./

Inside of /System/Library/Extensions/IOPlatformPluginFamily.kext/Contents/PlugIns/ACPI_SMC_PlatformPlugin.kext/Contents/Resources
you'll have a list of plist's. If you go to Apple > About This Mac > More Info > System Report > Hardware Overview you'll see a line that says "Model Identifier". That should match one of the plists in the that Resources folder.
Change the name and restart and kernel_task will no longer [bleep][bleep][bleep][bleep] itself.

[alex s]

Hi Focuret,

Thanks very much for the reply.

It sounds like you know what you're talking about.

Is this something which has previously been discussed?

The way you're describing it, it isn't a bug and we shouldn't expect a fix anytime soon.

Is this your take on it ?

The external monitor is causing the Macbook to heat up too much and it goes into a loop.

This would explain why I didn't have this problem on a smaller session sitting around 5% CPU.

There seems to be a heat / CPU threshold where things go [bleep] [bleep] mental.

Al

[JFreak]

Ouch... my ears are ringing for all this beeping

[Focuret]

Originally Posted by alex s

Hi Focuret,

Thanks very much for the reply.

It sounds like you know what you're talking about.

Is this something which has previously been discussed?

The way you're describing it, it isn't a bug and we shouldn't expect a fix anytime soon.

Is this your take on it ?

The external monitor is causing the Macbook to heat up too much and it goes into a loop.

This would explain why I didn't have this problem on a smaller session sitting around 5% CPU.

There seems to be a heat / CPU threshold where things go [bleep] [bleep] mental.

Al

Since I bought the laptop in 2011 I've had the kernel_task problem but I went overseas and never got a chance to take it in. I suspect it to be a hardware issue but I can't be sure because it's so random. Sometimes it happens without an external monitor being connected. Sometimes it's the power cord being connected. Sometimes it's Flash videos playing. And sometimes it just flips [bleep][bleep][bleep][bleep] and goes insane by itself while nothing else is running. It's all very strange but it all seems to boil down to a heat management issue. Removing the file can give me months of perfect usage but then it can start randomly overheating.

If you can, do take it in and tell them you're having the crazy kernel_task issue and you think it may be because of the heat sensor or thunderbolt port. Hopefully they'll know what you're talking about.

The issue is all over the net but I've never discussed it here -- only on Mac forums. Just 2 days ago I discovered the external monitor was the culprit and accidently found out standing it on its side fixed it. Until I figure something else out, I just have to unplug the monitor. It is an immense pain in the buttocks.

Have your session open and try standing it up on it's front side. See if that works. If that doesn't just rename that file and you should be good to go for a while. If after some months it all of the sudden goes to sleep, touch it and see how hot it is. If it's super hot then it auto slept to protect itself. If it starts happening more and more just rename the file back and restart. For me, I was good to go for a few weeks after renaming the file back but then it went crazy again and I had to rename the file. Again. It's a really weird back and fourth process but short of buying a new laptop, we don't have a choice. We got screwed and happened to get MBPs from the faulty batch.

[Focuret]

Originally Posted by JFreak

Ouch... my ears are ringing for all this beeping

Oh if you experienced our pain, you'd be beeping all over the place as well, lol

[alex s]

Just found this:

http://duc.avid.com/showthread.php?t=329216

[Bill Denton]

While it could well be a bug, there are a couple of questions that also need answering...

What are the temperatures where the computer is being used?

Is there anything around the computer that could obstruct the airflow to the machine?

As a broad general rule it is usually not a good idea to disable any of the temperature monitoring/management on your computer as you could end up with a bunch of fried parts...

[Focuret]

Originally Posted by Bill Denton

While it could well be a bug, there are a couple of questions that also need answering...

What are the temperatures where the computer is being used?

Is there anything around the computer that could obstruct the airflow to the machine?

As a broad general rule it is usually not a good idea to disable any of the temperature monitoring/management on your computer as you could end up with a bunch of fried parts...

For me it's not an issue of airflow or anything. It's just a pos. Google "kernel_task cpu" and you'll find thousands of posts about this stupid ass problem.

[Focuret]

Interesting.

This kernel extension is loaded on boot into userland, but interestingly, if you boot into safe mode (hold shift during boot), it is not loaded — and the kernel_task CPU spikes don't occur, even under heat-generating load. You can verify this by running `kextstat', which lists all loaded kernel extensions — run it in Terminal while booted normally and you should see an extension called 'com.apple.driver.AppleIntelPenrynProfile' loaded. Boot into safe mode by holding down shift before the chime and run `kextstat' again — no com.apple.driver.AppleIntelPenrynProfile, and no kernel_task CPU spike when generating heat (play a Flash video).

Read more here http://tech.superhappykittymeow.com/?p=258