Oracle uses v $ osstat view to query CPU usage

OS statistics
John also needs to eliminate the possibility that the host system is a bottleneck when carefully checking the user's performance problems. Before using Oracle for 10 Gbit/s, he can use operating system (OS) tools such as SAR and vmstat and infer some metric indicators that determine contention issues. In Oracle 10 Gb, OS-level metrics are automatically collected in the database. To view potential host contention problems, John performs the following query on the V $ osstat View:
Select * from V $ osstat;
CodeThe output in Listing 6 shows various OS-level metric elements. All time elements are in the unit of per second. John learned from the results shown in code listing 6 that a CPU in the system is idle for 51025805 seconds (idle_ticks) and busy for 2389857 seconds (busy_ticks ), this indicates that the CPU is about 4% busy.

 

2389857/(51025805 + 2389857) = 4%

 

He concluded that CPU is not a bottleneck in the host. Note that if the host system has more than one CPU, the header contains the AVG _ prefix column. For example, avg_idle_ticks displays the average value of these metrics for all CPUs.