For more details about the CPU virtualization Overhead, you can go to Virtualization drill down | CPU virtualization Overhead chart, the value in Spotlight on Oracle homepage is the same as it.
Here’s the help for this chart:
- CPU Virtualization Overhead shows if ESX is restricting the virtual machine's access to the CPU.
- System -> Amount of CPU time ESX spent on system processes. This value is typically less than 1%.
- Ready -> Amount of CPU time this virtual machine wanted access to the CPU but had to wait for it to become available. A low value (less than 15%) indicates that the virtual machine is getting the CPU it requires. A high ready time indicates that the virtual machine is having to frequently wait to gain access to the physical CPU(s). This may result in the applications running on the virtual machine providing noticeable latency to end users.
- Excluded -> Percentage of time that the virtual machine is excluded access to the physical CPU(s) due to a configured CPU limit.
In vSphere you can find similar value from Performance | Advanced | chart options | select the same counters (the value in Spotlight has been calculated as a percentage):
