How to re-enable CPU Cores after isolcpus

Question

I'm running some processes on a Jetson NX and I was trying to isolate 3 of the cores so I could use taskset and dedicate them to my python script which incorporated multi processing. To do this, I followed a few tutorials and modified my /boot/extlinux/extlinux.conf file to be:

TIMEOUT 30
DEFAULT primary

MENU TITLE L4T boot options

LABEL primary
      MENU LABEL primary kernel
      LINUX /boot/Image
      INITRD /boot/initrd
      APPEND ${cbootargs} quiet root=/dev/mmcblk0p1 rw rootwait rootfstype=ext4 console=ttyTCU0,115200n8 console=tty0 fbcon=map:0 net.ifnames=0 isolcpus=3-5

This worked fine for my needs and when I ran cat /sys/devices/system/cpu/isolated it outputted 3-5. Now I'm trying to bring back cores 3 and 4, so I modified the extlinux.conf file to say:

TIMEOUT 30
DEFAULT primary

MENU TITLE L4T boot options

LABEL primary
      MENU LABEL primary kernel
      LINUX /boot/Image
      INITRD /boot/initrd
      APPEND ${cbootargs} quiet root=/dev/mmcblk0p1 rw rootwait rootfstype=ext4 console=ttyTCU0,115200n8 console=tty0 fbcon=map:0 net.ifnames=0 isolcpus=5

and I rebooted my Jetson. However It still says cores 3-5 are isolated. Is there some other steps I need to take to re-enable these cores?

Answer 1

You need to update your bootloader using its proper script. You're using extlinux bootloader and I believe you're running Alpine Linux. Try running:

update-extlinux

Reboot and recheck. Read more on ArchLinux Wiki.