You can view the performance details of each CPUs of your machine in the top command by pressing 1 (number one) while the top command is running.one).
$ top
top - 09:28:33 up 2 days, 12:46, 2 users, load average: 0.61, 0.41, 0.18
Tasks: 90 total, 1 running, 89 sleeping, 0 stopped, 0 zombie
Cpu(s): 17.0%us, 1.4%sy, 0.0%ni, 81.6%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 1025468k total, 793568k used, 231900k free, 120836k buffers
Swap: 1951856k total, 0k used, 1951856k free, 342384k cached when i pressed ‘1’ i got the details shown below.
top - 09:29:25 up 2 days, 12:47, 2 users, load average: 0.78, 0.50, 0.22 Tasks: 90 total, 1 running, 89 sleeping, 0 stopped, 0 zombie Cpu0 : 25.5%us, 1.9%sy, 0.0%ni, 67.8%id, 4.7%wa, 0.0%hi, 0.1%si, 0.0%st Cpu1 : 16.5%us, 1.3%sy, 0.0%ni, 82.2%id, 0.1%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 1025468k total, 801648k used, 223820k free, 120944k buffers Swap: 1951856k total, 0k used, 1951856k free, 342500k cached
the second shows data of individual CPUs.