The mpstat tool allows you to query and monitor statistics related to processors and its cores.
$ sudo apt install sysstat
$ mpstat -P ALL
Linux 4.4.0-17763-Microsoft (foobar) 01/14/21 _x86_64_ (4 CPU)
14:30:02 CPU %usr %nice %sys %iowait %irq %soft %steal %guest %gnice %idle
14:30:02 all 5.53 0.00 5.43 0.00 0.33 0.00 0.00 0.00 0.00 88.70
14:30:02 0 5.77 0.00 8.29 0.00 2.10 0.00 0.00 0.00 0.00 83.84
14:30:02 1 4.25 0.00 6.21 0.00 0.16 0.00 0.00 0.00 0.00 89.39
14:30:02 2 6.55 0.00 5.51 0.00 0.08 0.00 0.00 0.00 0.00 87.86
14:30:02 3 5.06 0.00 4.30 0.00 0.04 0.00 0.00 0.00 0.00 90.60
$ mpstat -P ALL -o JSON
Tried with: sysstat 11.6 and Ubuntu 18.04