I'm testing linux cpu hotpluging on normal desktop 8-core AMD machine. Problem seems that after onlining a CPU again taskset and kernel refuses to move and/or schedule any tasks on the core. E.g. doing:
echo 0 | sudo tee /sys/devices/system/cpu/cpu7/online
echo 1 | sudo tee /sys/devices/system/cpu/cpu7/online
taskset -c 7 bash
Fails... I don't know why taskset refuses to migrate any threads to the hotpluged cores. I have intend to use this to improve the kernel NO_HZ tickless operation by forcing Local timer interupts (LOC) off from cores 2-7. The kernel NO_HZ documentation suggests this possibility.
I'm running mainline 4.4.6 PREEMPT kernel on Linux Mint 17.3. The kernel is self-compiled though as stock mint kernels are missing several features/drivers that I require.
