include/linux/sched/loadavg.h

   1 #ifndef _LINUX_SCHED_LOADAVG_H
   2 #define _LINUX_SCHED_LOADAVG_H
   3
   4 /*
   5  * These are the constant used to fake the fixed-point load-average
   6  * counting. Some notes:
   7  *  - 11 bit fractions expand to 22 bits by the multiplies: this gives
   8  *    a load-average precision of 10 bits integer + 11 bits fractional
   9  *  - if you want to count load-averages more often, you need more
  10  *    precision, or rounding will get you. With 2-second counting freq,
  11  *    the EXP_n values would be 1981, 2034 and 2043 if still using only
  12  *    11 bit fractions.
  13  */
  14 extern unsigned long avenrun[];         /* Load averages */
  15 extern void get_avenrun(unsigned long *loads, unsigned long offset, int shift);
  16
  17 #define FSHIFT          11              /* nr of bits of precision */
  18 #define FIXED_1         (1<<FSHIFT)     /* 1.0 as fixed-point */
  19 #define LOAD_FREQ       (5*HZ+1)        /* 5 sec intervals */
  20 #define EXP_1           1884            /* 1/exp(5sec/1min) as fixed-point */
  21 #define EXP_5           2014            /* 1/exp(5sec/5min) */
  22 #define EXP_15          2037            /* 1/exp(5sec/15min) */
  23
  24 #define CALC_LOAD(load,exp,n) \
  25         load *= exp; \
  26         load += n*(FIXED_1-exp); \
  27         load >>= FSHIFT;
  28
  29 extern void calc_global_load(unsigned long ticks);
  30
  31 #endif /* _LINUX_SCHED_LOADAVG_H */