How to profile a driver

[Bharma Ji]

I am trying to optimize a driver for performance. What are the standard ways
to profile a driver?

 My problem at the moment is that when I run a test and max out the CPU,
then the system % is 60 and user % is 30. I wanted to find out how much time
is being spent in the driver(and within it, if possible in what components).
Can this be determined and if so, how to figure this out.