aperf/mperf

[Andriy Gapon]

Many modern processors provide APERF and MPERF MSRs which allow to easily and
reliable calculate average CPU performance level over some interval of time.
This also allows to notice things like performance boost, which is generally
hidden from software.
What would be a proper place to add code that would measure APERF/MPERF ratio?
When should trigger such a measurement and over what interval?
Ideas?

Thanks a lot!
-- 
Andriy Gapon