How to solve kernel_task high CPU usage?

Discussion in 'MacBook Pro' started by fantasticbobski, Feb 14, 2014.

  1. Douglas Barnes macrumors newbie

    Douglas Barnes

    Joined:
    Oct 7, 2015
    #76
    Updating to El Cap reinstalls the offending .plist file, and tacks on "System Integrity Protection" to make sure you are unable to fix your MacBook. Here's the way around that.

    1. Reboot and hold Command + r after the chime. (This should take forever and a day, thanks to the kernel_task issue.)
    2. Go to Utilities > Terminal
    3. In the terminal, type the following: csrutil disable; reboot
    4. Proft
     
  2. Grenskie macrumors newbie

    Joined:
    Nov 11, 2015
    #77
    How exactly did you get OS X to allow you to modify that file I keep getting a pop up that says that file cannot be modified or deleted because it is required by OS X
     
  3. Douglas Barnes macrumors newbie

    Douglas Barnes

    Joined:
    Oct 7, 2015
    #78
    Read my post above yours.
     
  4. A Fish Out Of Water macrumors newbie

    Joined:
    Nov 21, 2015
    #79
    I think the method worked for me, cause it seems like it's running faster, but when I check Activity Moniter, it still says that kernal_task is running at the same level. Did it not work, because it seems like it may have worked, but I can't tell.
     
  5. fcurrie21 macrumors newbie

    Joined:
    Dec 22, 2015
    #80
    oh my god. Thank you ever so much to fantasticbobski and Douglas Barnes. I don't know how it worked, but it has! I am experienced in fixing mainly PCs and on this MacBook I have changed the HDD to an SSD, changed the hard drive cable as I read that this is a common and difficult to diagnose fault on the early 2011 MacBook Pros and finally this trick worked! Went from 98% system usage at rest to about 4%! Fan was running full blast before and still is now so i've got that to work on. But thanks ever so much, I'm going to have one happy girlfriend.

    Cheers.
     
  6. EkimReldar macrumors newbie

    Joined:
    Dec 22, 2015
    #81
    Mike,

    I had no right to do this but, I copy/pasted this

    Code:
    sudo mv /System/Library/Extensions/AppleSMCLMU.kext ~
    and now my computer has more beach ball time out then ever. Sorry to ask but can you tell me how to undo this command?

    Thanks


     
  7. EkimReldar macrumors newbie

    Joined:
    Dec 22, 2015
    #82
    By the way, I have an early 2011 macbook pro 15" with 16 GB ram
     
  8. osart11 macrumors newbie

    osart11

    Joined:
    Dec 25, 2015
    #83
    Hello,

    I cannot find IOPlatformPluginFamily.kext
    can u please help?
     
  9. Kix_ macrumors newbie

    Kix_

    Joined:
    Dec 25, 2015
    #84
    I've had the same experience (kernel_task consuming up to 500%+ CPU time according to Activity Monitor), and here's how I solved it. But first, some things worth pointing out:

    The kernel_task is a core operating system component which basically manages things such as communication between the hardware and the OS. If the kernel_task is eating too much CPU time, it's usually indicative of something wrong with the hardware.

    .kext files are Kernel EXTensions. They're analogous to Windows drivers such that they allow the OS to communicate properly with the hardware components.

    As you might figure out, disabling kext files (like some guides advise you to) is a very reckless move and a terrible idea. Essentially, if you remove a kext file, you're removing a layer of communications between the OS and hardware. The ACPI___.kext file for example, deals with system power, battery management, and voltage levels. As you might imagine, if you were to silence this kext file, you're exposing your system to a ton of dangerous stuff relating to power management (worst case would be a fried battery or motherboard).

    Remember how high kernel_task CPU usage usually means something in your hardware gone awry? In my case, the fans were not spinning properly, thus making my system overheat and causing the kernel_task to panic. This happened because I previously installed a tool called Macs Fan Control which let me max out my fan speeds at all times, and forgot to turn it on. As a result, my fan speeds were locked at a low 1000-ish RPM while trying to play a game, and as you can imagine, it heated up my system pretty well. I turned on Macs Fan Control and set my RPM to max, and the kernel_panic task chilled out. If I disabled my kext file for sensor control or fans, the kernel_task would probably have chilled all the same BUT with the added danger of me overheating my system.

    Some things worth trying:
    - Disable peripherals (a faulty USB device pulling higher voltage might be an ideal culprit, as well as an HDMI peripheral gone bonkers)
    - Check temperatures and fan speeds (this is what happened to mine)
    - Check virtualization tools (such as Parallels and VMWare Fusion; sometimes they cause the kernel_task due to the way they handle system resources)
    - Try a restart and SMC refresh

    Cheers
    Kix_
     
  10. EkimReldar, Dec 26, 2015
    Last edited: Dec 26, 2015

    EkimReldar macrumors newbie

    Joined:
    Dec 22, 2015
    #85
    Can anyone help me, I need to REVERSE this copy/paste.

    Code:
    sudo mv /System/Library/Extensions/AppleSMCLMU.kext ~

    I copied it in and it is wreaking havoc on my system. Is there any way to undo this?
     
  11. EkimReldar macrumors newbie

    Joined:
    Dec 22, 2015
    #86
     
  12. Weaselboy Moderator

    Weaselboy

    Staff Member

    Joined:
    Jan 23, 2005
    Location:
    California
    #87
    First let's make sure the file is still where you moved it. Click the Desktop the hit shift-command-g (all three at once) and enter ~ in the box then hit return. That should open a Finder window at the base of your user folder. Is the file AppleSMCLMU.kext still there? If it is, leave it alone and try the command below to put it back where it was. Reboot after.

    Code:
    sudo mv ~/AppleSMCLMU.kext /System/Library/Extensions/
     
  13. EkimReldar macrumors newbie

    Joined:
    Dec 22, 2015
    #88
    I went to my user folder, did not see appleSMCLMU.kext

    file://localhost/Users/michaelradler/Desktop/Screen%20Shot%202015-12-26%20at%2011.29.39%20PM.png

    This is what I am basically seeing when I arrive there
     

    Attached Files:

  14. EkimReldar, Dec 26, 2015
    Last edited: Dec 26, 2015

    EkimReldar macrumors newbie

    Joined:
    Dec 22, 2015
    #89
    Sorry, I realized I need to enter ~ in the box and hit return, just did, still not there
     
  15. EkimReldar, Dec 26, 2015
    Last edited: Dec 26, 2015

    EkimReldar macrumors newbie

    Joined:
    Dec 22, 2015
  16. EkimReldar macrumors newbie

    Joined:
    Dec 22, 2015
    #91
    I went there and it was not there…I guess that's not a good start huh? Any other ideas? Thanks

     
  17. EkimReldar macrumors newbie

    Joined:
    Dec 22, 2015
    #92
    If you are asking me sorry, wrong guy, anyone else able to help osart11?


     
  18. Weaselboy Moderator

    Weaselboy

    Staff Member

    Joined:
    Jan 23, 2005
    Location:
    California
    #93
    Nope... that first command would have moved the file to ~ which is the base of your users folder, and from your screenshots it looks like it is not there, so you have nothing to copy back. You must have deleted the file at some point.

    At this point you will need to command-r boot to recovery and just reinstall the OS to get the file back. Don't erase anything, just reinstall and all your data will still be there.

    You should backup first though just to be safe.
     
  19. EkimReldar macrumors newbie

    Joined:
    Dec 22, 2015
    #94
    Thanks so much, I'll d that now and maybe a clean OS will solve some other issues I'm sure I had going on. Will update this thread after to report my progress, thanks again.


     
  20. squamish macrumors newbie

    Joined:
    Jan 11, 2016
    #96
    My battery was/ is dying. Suddenly my machine slowed to a crawl but this worked for me.! Thanks.
     
  21. colshefsky macrumors newbie

    colshefsky

    Joined:
    Jan 12, 2016
    #97
    Works for me too! Thanks everyone! My CPU is as good as new :D
     
  22. zeusthedino macrumors newbie

    zeusthedino

    Joined:
    Jan 14, 2016
    #98
    Im getting tired of my macbook pro 2011 17 inch getting hot so quickly. I changed the thermal paste and so now it doesnt reach 90c as it used to, but it still gets very hot which is annoying because the keyboard becomes hot too.
    Should I do the .kext fix? I need a fix for this heat problem
     
  23. VanessaKing macrumors newbie

    VanessaKing

    Joined:
    Feb 10, 2016
    #99
    I've been using mine for 24 hours since moving this one out of my extensions folder, and it's working great! Apparently it's a sensor extension for MBP 3,1 + 4,1 + 5,1 and since I've got a 6,1 MBP, it was completely unnecessary. Thanks for the great tip, Mike!!
     
  24. VanessaKing macrumors newbie

    VanessaKing

    Joined:
    Feb 10, 2016
    #100
    Quick update, I'm still kernel panic-free, but I think this kext handles the keyboard backlight sensor. Since I removed it, my keyboard's backlight doesn't work—not manually or automatically. I'm happy to type in brighter light though, if it means no more crashing, overheating, runaway fanning.
     

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