UCHAR
PopCalculateBusyPercentage(
  IN  PPROCESSOR_POWER_STATE  PState
  );

Routine Description:

    This routine is called within the context of the target processor
    to determine how busy the processor was during the previous time
    period.

Arguments:

    PState  - Power State Information of the target processor

Return Value:

    Percentage value representing how busy the Processor is