Yuan Yao, An Oracle ACE's Blog

In our previous article, we discussed How Oracle Calculates Host CPU Usage. Now we’ll explore Oracle instance CPU Usage.

Instance-level CPU usage shows how much Oracle itself is consuming from the host’s CPU resources.

Using the total CPU time used by the Oracle instance (17,562.40 seconds, from Time Model Statistics):

Using the total CPU time from OS Stats: BUSY_TIME (1,905,713) + IDLE_TIME (12,222,778) = 14,128,491 hundredths = 141,284.91 seconds.

%Total CPU = 17,562.40 / 141,284.91 = 12.4%

%Busy CPU = 17,562.40 / 19,057.13 = 92.2%