After installing big sur, i noticed my 2017 macbook pro would lag every few hours, during the lag i basically cannot do anything because it was so laggy, but one time managed to open activity monitor when it was lagging and i saw kernel_task was using 400% or higher cpu, ive already tried to restart my computer but it just comes back after few minutes, ive also tried reseting my smc and unplugging my cords but it still didnt work, how can I fix this? (sorry if my english is bad, english is not my native language)

also, my mac's model id is 14,2

2 Answers 2


Your mac may be overheating, try switching the charging ports.


We need to understand what the kernel is doing and then make an educated guess as to why. A straightforward way to accomplish this is by gathering a spindump.

  1. Run the following Terminal command to enable kernel symbolication: sudo nvram boot-args="keepsyms=1". Make sure to copy-paste this so that you're entering straight quotes rather than curly/“smart” quotes. (If you get a permission error, you will first need to disable System Integrity Protection. You can re-enable it after you're done with this investigation.)
  2. Reboot your machine and don’t open any apps except for Terminal.
  3. In Terminal, enter the following command, press Return, type in your password, but do not press Return again yet: sudo spindump -reveal -noProcessingWhileSampling
  4. Continue using your computer as normal until you start experiencing lag.
  5. As soon as you feel lag, go to the Terminal window where you entered your password and press Return so that the command begins to execute. Do not do anything else on the computer while it's running, otherwise you will distort the data collection.
  6. After waiting for >10 seconds to collect a sample and another minute or two to symbolicate and format, you’ll get a file in /tmp/spindump.txt that contains a stackshot of every process.
  7. Upload the file to PasteBin or some equivalent place and add the link to it to your original question.

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