Well, there is no HW tool to do such a measurement, so you would need to do it by software.
Some examples you can find at the link below:
How to calculate CPU utilization | Embedded
As you may already know, the XGATE is a generic RISC CPU core and it is intended to be used as auxiliary core to unload the S12X CPU (main core). It works as an event triggered co-processor, mainly used for processing the interrupt events.
I hope you'll find this information useful.
Regards,
iggi
