mpstat is a very handy terminal utility for of showing per-processor or per-core system statistics such as user process load, system load, I/O statistics, IRQ activity and other useful information.
mpstat is typically invoked with a time interval as an argument. For example,
will show system statistics once every second. Those using NUMA systems can add
-N ALL before the time interval to get per-node statistics. Adding
-P ALL on any machine will list detailed per-CPU-core statistics:
mpstat -P ALL 1
will show you what each and every CPU core is doing each second.