When CPU n is disabled , all CPUs > n report 0%
When a logical cpu is disabled using the command
echo 0 | sudo tee /sys/devices/system/cpu/cpuN/online
where N is the number of a logical cpu other than 0, Gnome System Monitor reports all cores from N to the last core as 0% even when lscpu -e , cat /sys/devices/system/cpu/cpu*/online , and cat /proc/cpuinfo all indicate otherwise