+ double nsec_per_cycle; //Nsec per cycle
+ guint64 one_overflow_nsec; //nsec for one overflow
+ gint64 overflow_nsec; //precalculated nsec for overflows
+ //can be negative to include value
+ //of block start cycle count.
+ //incremented at each overflow while
+ //reading.
+ //LttCycleCount cycles_per_nsec_reciprocal; // Optimisation for speed