Therefore, the average CPU utilization is only 7% (0.0719 = 172.50 seconds / 2,400 seconds). At only 7% CPU utilization, regardless of the number of CPU cores, the system is operating nowhere near the response-time curve elbow.

Based on v$osstat data, you also can calculate the average operating system CPU utilization. Just remember the CPU consumed requires two samples: the initial and the final. If you take only one sample, you will probably notice the bogus utilization calculation will far exceed 100%. The CPU consumed is the final BUSY_TIME value minus the initial value. The CPU time available will be the sample interval multiplied by the number of CPU cores. And don't forget to convert all time to the same unit, such as seconds.

In summary, to determine the average CPU utilization, some tools you can use are vmstat, sar, /proc/stat, and even v$osstat. So, if you don't have the operating system privileges you need, starting with Oracle Database 10g, you can still calculate the utilization.