How to make cpu0 offline?

Question

I want to make cpu0 offline. I have dual core laptop. I can make cpu1 offline ( using offline file ) but can't make cpu0 offline. How to do this ?

Answer 1

to enable a cpu0

you can use this

echo 1 | sudo tee /sys/devices/system/cpu/cpu0/online

and to disable

echo 0 | sudo tee /sys/devices/system/cpu/cpu0/online

Answer 2

I've also found, certain systems cannot disable CPU0. I think usually this happens because the interrupt line is wired to CPU0, so the APIC cannot signal CPU1 on up (turning off CPU0 would cut off all interrupts and the system would lock up.)