Check cpu

The plugin can handle trigging on either total used CPU time (default) or total idle CPU time. It calculates a 5 second average for each values which means that Idle% + Used% isn't always 100%.

All values are correctly calculated depending on the number of ticks per second the kernel uses and the number of CPUs present in the machine (No consideration is taken to the fact that it might not be a multi-processor machine but a uni-processor with Hyper Threading).