11 ms·

I had a strange problem appear after I spilled tea on my 2010 MBP last year. Continually, kernel_task was using an entire core (150-250% in top) and no amount o

I had a strange problem appear after I spilled tea on my 2010 MBP last year. Continually, kernel_task was using an entire core (150-250% in top) and no amount of reboots could fix this. The built-in hardware diagnostic indicated it was not compatible with my Mac, and I could find nothing else that apparently was wrong. My computer was running very slowly though, and the system load was always over 4. Finally I found through research that this is somehow related to power management. Apparently the system will have the CPU loop simple operations to prevent the processor from doing actual work and heating up. Sure enough, disabling power management by hacking a kernel extension made the kernel_task problem go away. My Mac has run perfectly for three months ever since I made that fix, after being nearly disabled for a year.

Moto7451 13y ago
I remember having this same problem on a hackintosh. Installing the NullPowerManagement kext was the usual fix back then since DSDT patches were brand new and not well known by the community. If that kext is still available and compatible with 10.9 it's probably a good way to handle this until they fix it.
cliveowen 13y ago
Damn, my 2009 Macbook has been running very slowly for the past 4 months or so and no amount of rebooting would resolve the problem. I was actually puzzled when it slowed down to a crawl becoming basically useless and would even restart with the same slowness. Could you elaborate on your fix?
- btown 13y ago
  See my comment above - it might help.
  - cliveowen 13y ago
    Thank you.
- threeseed 13y ago
  Also try running sudo fs_usage in Terminal. Every line printed is a disk read/write and since you would be on an older machine with slower I/O you need to reduce the number of lines printed. One useful trick is to add folders to Spotlight's Privacy section e.g. source code, downloads, torrent locations, game files etc.
- code_duck 13y ago
  This is the post that provided the fix that worked for me: http://www.rdoxenham.com/?p=259 http://www.rdoxenham.com/?p=259
btown 13y ago
Had the exact same problem (minus the spilled tea, but I'm often running my computer very hot so I'm not surprised) on OS 10.8 on a 2011 (?) MBP, and did exactly this to fix it. I verified that the problem was with some sort of IntelACPI... [sic] module using a DTrace script (been a while but I can try to find it if anyone wants... basically that module was using up a large amount of CPU whenever there was load, such as when I launched a game. Long story short, the step-by-step to fix it is here: http://www.rdoxenham.com/?p=259 http://www.rdoxenham.com/?p=259 (cached: http://webcache.googleusercontent.com/search?q=cache:UPanIg_jwKQJ:www.rdoxenham.com/%3Fp%3D259&hl=en&gl=us&strip=1 http://webcache.googleusercontent.com/search?q=cache:UPanIg_... ) Been working like a charm for about 13 months now, and it's survived multiple minor 10.8.x upgrades since then. YMMV may vary with 10.9, and since they supposedly changed power management, I wouldn't touch that upgrade with a [Mac OS] 10 foot pole.
- code_duck 13y ago
  The fix for me was to simply delete the power profile from my MacBook model in a kext config directory. Everything was fine until I upgraded to 10.8.5, and then to my system would not boot at all – feeling with the kernel panic very early in booth that had something to do with AppleIntelCpuPowerManagement.kext. I completely reinstalled and install Mavericks, and then repeated the original fix. It worked fine and my system is doing great running Mavericks.
  - code_duck 13y ago
    Uh, "feeling with the kernel panic very early in booth" meaning, boot failed with a kernel panic. I was kind of confused by what I read about power management having been changed in Mavericks, but it turned out that whatever is relevant to this issue has not changed. As I noted the same solution fixed the same problem.

Moto7451 13y ago

I remember having this same problem on a hackintosh. Installing the NullPowerManagement kext was the usual fix back then since DSDT patches were brand new and not well known by the community. If that kext is still available and compatible with 10.9 it's probably a good way to handle this until they fix it.

cliveowen 13y ago

Damn, my 2009 Macbook has been running very slowly for the past 4 months or so and no amount of rebooting would resolve the problem. I was actually puzzled when it slowed down to a crawl becoming basically useless and would even restart with the same slowness. Could you elaborate on your fix?

btown 13y ago
See my comment above - it might help.
- cliveowen 13y ago
  Thank you.
threeseed 13y ago
Also try running sudo fs_usage in Terminal. Every line printed is a disk read/write and since you would be on an older machine with slower I/O you need to reduce the number of lines printed. One useful trick is to add folders to Spotlight's Privacy section e.g. source code, downloads, torrent locations, game files etc.
code_duck 13y ago
This is the post that provided the fix that worked for me: http://www.rdoxenham.com/?p=259 http://www.rdoxenham.com/?p=259

btown 13y ago

Had the exact same problem (minus the spilled tea, but I'm often running my computer very hot so I'm not surprised) on OS 10.8 on a 2011 (?) MBP, and did exactly this to fix it. I verified that the problem was with some sort of IntelACPI... [sic] module using a DTrace script (been a while but I can try to find it if anyone wants... basically that module was using up a large amount of CPU whenever there was load, such as when I launched a game. Long story short, the step-by-step to fix it is here: http://www.rdoxenham.com/?p=259 http://www.rdoxenham.com/?p=259 (cached: http://webcache.googleusercontent.com/search?q=cache:UPanIg_jwKQJ:www.rdoxenham.com/%3Fp%3D259&hl=en&gl=us&strip=1 http://webcache.googleusercontent.com/search?q=cache:UPanIg_... ) Been working like a charm for about 13 months now, and it's survived multiple minor 10.8.x upgrades since then. YMMV may vary with 10.9, and since they supposedly changed power management, I wouldn't touch that upgrade with a [Mac OS] 10 foot pole.

code_duck 13y ago
The fix for me was to simply delete the power profile from my MacBook model in a kext config directory. Everything was fine until I upgraded to 10.8.5, and then to my system would not boot at all – feeling with the kernel panic very early in booth that had something to do with AppleIntelCpuPowerManagement.kext. I completely reinstalled and install Mavericks, and then repeated the original fix. It worked fine and my system is doing great running Mavericks.
- code_duck 13y ago
  Uh, "feeling with the kernel panic very early in booth" meaning, boot failed with a kernel panic. I was kind of confused by what I read about power management having been changed in Mavericks, but it turned out that whatever is relevant to this issue has not changed. As I noted the same solution fixed the same problem.