Collecting hypervisor call stats

[Mike Kravetz]

We would like to add code that gathers statistics about hypervisor calls.
It would keep track of things like # of calls made for each opcode as well
as time spent processing the calls.

The 'obvious' place to gather such statistics would be from within the
routines making hcalls in hvCall.S.  Once thing that I have noticed is
the following comment at the beginning hvCall.S:

 * NOTE: this file will go away when we move to inline this work.

So, it appears someone thought/thinks these routines should be inlined.  
I assume this is for performance reasons?  If this is the case, then I
suspect gathering of statistics (which would introduce overhead) would
meet resistance?

Comments about the feasibility of adding such statistic gathering code
would be appreciated.

Thanks,
-- 
Mike