What is "kernal_task" and how do I stop this?

Discussion in 'MacBook Pro' started by Krafty, Feb 7, 2014.

  1. Krafty, Feb 7, 2014
    Last edited: Feb 7, 2014

    Krafty macrumors 601

    Krafty

    Joined:
    Dec 31, 2007
    Location:
    La La Land
    #1
    So recently (about a week ago) I've been noticing this issue with my md-2010 17" MBP. For some reason, kernal_task seems to be spiking in CPU load. I never knew what this problem was...until I disconnected my TV I had plugged into it via mDP. So I tried it again and was able to replicate the issue, so for some reason up until recently, kernal_tasks spikes in CPU (thus, causing the fans to blare) whenever I connect my TV to my MBP via mDP-to-DVI. It's never done this before. Here's a screencap when watching a film using VLC on my TV connected to my MBP via mDP:

    [​IMG]
    As soon as I disconnect, it returns to normal. I can't force it to quit & a reboot was no avail. Any solutions or what could be causing this?

    I am running Snow Leopard (10.6.8).
     
  2. simsaladimbamba

    Joined:
    Nov 28, 2010
    Location:
    located
    #2
  3. simonsi macrumors 601

    simonsi

    Joined:
    Jan 3, 2014
    Location:
    Auckland
    #3
    kernel_task IS your operating system....it is high CPU at that time because it is probably busy driving graphics etc at big resolution for the TV?

    Edit to add: kernel_task is doing several things, running the machine, servicing the other apps running (like VLC), driving the windows and system monitor you are looking at etc etc....
     
  4. Krafty thread starter macrumors 601

    Krafty

    Joined:
    Dec 31, 2007
    Location:
    La La Land
    #4
    I am on 10.6.8, that was a typo.

    But it's never done that before, and no the TV is pretty pathetic (not complaining, it gets the job done), the resolution is only 1024x576. It's a Sanyo 32" Class 720p 60Hz LCD HDTV, DP32649. But of all the times I've dual-monitored, I've never noticed the CPU spiking like that until last weekend. Even searching on Apple support, I see people with the same issue but different culprits (most couldn't find a solution).

    So, this is normal then? Cause I swear it's never done this before (even when running Coda & Adobe programs, the fans would blare of course but the CPU was pretty moderate, never spiking @ 100% all the time). The first time it did that, I wasn't dong anything. As mentioned, I even rebooted and just let it sit and the CPU spiked again with kernal_task going over 200%.
     
  5. simonsi macrumors 601

    simonsi

    Joined:
    Jan 3, 2014
    Location:
    Auckland
    #5
    Well the cpu just does its thing, of itself high cpu isn't an issue but if something is causing it without a good reason that is an issue. Obviously if it only spikes while the TV is connected and running VLC it must somehow be graphics related, I'd connect the TV and see what resolution the MBP is trying to drive it at.

    Then, when you unplug the TV does kernel_task fall back to nothing or is the TV just the last straw and really there is something else running that didn't used to??? High CPU could just be that many things are running but without the TV it doesn't run hard enough to use the fans and draw your attention to it.
     
  6. Krafty thread starter macrumors 601

    Krafty

    Joined:
    Dec 31, 2007
    Location:
    La La Land
    #6
    In the display settings I have it set to 720p, it's always been on that in the past years.

    It's the TV. At first I wasn't sure but it only does it when the TV is connected.
     
  7. simonsi macrumors 601

    simonsi

    Joined:
    Jan 3, 2014
    Location:
    Auckland
    #7
    I'm not sure you got my point. You have always connected this TV and nothing has changed there, but you notice high CPU when the TV is connected. My question is whether something else has changed and is consuming extra CPU so now when you connect the TV, CPU goes up by the same amount as previous but now the total CPU is high enough to cause an issue....?

    So previously total CPU was:

    OSX (say 5%)+ TV graphics (say 20%) = 25% no fans or lagging

    Now:

    OSX (say 5%)+ Something else (say 20%), + TV graphics (say 20%) = 45% fans come on etc....

    But you would need to look carefully at the CPU util without the TV to see....

    If nothing has changed, then nothing would be different, something clearly has changed, we just don't know what it is yet....
     
  8. maflynn Moderator

    maflynn

    Staff Member

    Joined:
    May 3, 2009
    Location:
    Boston
    #8
    I wouldn't be randomly killing processes, especially if you don't know what they are. If you;re dealing with performance issues, then I'd look at what is installed, or updating the system to a newer version of OSX
     

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