This means the CPU subsystem is operating on average at 100% utilization! We should have expected this, since Oracle is consuming 94% of all the available CPU. Calculating both Oracle CPU utilization and the operating system CPU utilization, we have a very nice confirmation that this is the only instance running on the database server and also that the CPU subsystem is experiencing a raging bottleneck.

The utilization formula implies a linear relationship between requirements and utilization. In other words, if the requirements double, so will the utilization. When you are asked, "But how do you know it really works like this?" show the graph in Figure 9-7, or better yet, create one yourself. While no real Oracle system will match this perfectly, for CPU-intensive systems, the linearity is very evident.

Figure 9-7 is an example of using SQL executions as the workload (logical IO would have also worked very well). The solid line is the actual sample data plotted, and the dotted line is a linear trend line added by Microsoft Excel. The correlation between the real data and the trend line is 0.9328, which represents a very strong correlation! In the upcoming sections, I will demonstrate how to use this linear relationship when anticipating the impact of a firefighting solution.