include/linux/sched/loadavg.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_SCHED_LOADAVG_H
   3 #define _LINUX_SCHED_LOADAVG_H
   4
   5 /*
   6  * These are the constant used to fake the fixed-point load-average
   7  * counting. Some notes:
   8  *  - 11 bit fractions expand to 22 bits by the multiplies: this gives
   9  *    a load-average precision of 10 bits integer + 11 bits fractional
  10  *  - if you want to count load-averages more often, you need more
  11  *    precision, or rounding will get you. With 2-second counting freq,
  12  *    the EXP_n values would be 1981, 2034 and 2043 if still using only
  13  *    11 bit fractions.
  14  */
  15 extern unsigned long avenrun[];         /* Load averages */
  16 extern void get_avenrun(unsigned long *loads, unsigned long offset, int shift);
  17
  18 #define FSHIFT          11              /* nr of bits of precision */
  19 #define FIXED_1         (1<<FSHIFT)     /* 1.0 as fixed-point */
  20 #define LOAD_FREQ       (5*HZ+1)        /* 5 sec intervals */
  21 #define EXP_1           1884            /* 1/exp(5sec/1min) as fixed-point */
  22 #define EXP_5           2014            /* 1/exp(5sec/5min) */
  23 #define EXP_15          2037            /* 1/exp(5sec/15min) */
  24
  25 #define CALC_LOAD(load,exp,n) \
  26         load *= exp; \
  27         load += n*(FIXED_1-exp); \
  28         load >>= FSHIFT;
  29
  30 extern void calc_global_load(unsigned long ticks);
  31
  32 #endif /* _LINUX_SCHED_LOADAVG_H */