extern void stat_calc_lat_m(struct thread_stat *ts, double *io_u_lat);
extern void stat_calc_lat_u(struct thread_stat *ts, double *io_u_lat);
extern void stat_calc_dist(unsigned int *map, unsigned long total, double *io_u_dist);
+extern void reset_io_stats(struct thread_data *);
static inline int usec_to_msec(unsigned long *min, unsigned long *max,
double *mean, double *dev)