LXR linux/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 */
  15extern unsigned long avenrun[];         /* Load averages */
  16extern 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/*
  26 * a1 = a0 * e + a * (1 - e)
  27 */
  28static inline unsigned long
  29calc_load(unsigned long load, unsigned long exp, unsigned long active)
  30{
  31        unsigned long newload;
  32
  33        newload = load * exp + active * (FIXED_1 - exp);
  34        if (active >= load)
  35                newload += FIXED_1-1;
  36
  37        return newload / FIXED_1;
  38}
  39
  40extern unsigned long calc_load_n(unsigned long load, unsigned long exp,
  41                                 unsigned long active, unsigned int n);
  42
  43#define LOAD_INT(x) ((x) >> FSHIFT)
  44#define LOAD_FRAC(x) LOAD_INT(((x) & (FIXED_1-1)) * 100)
  45
  46extern void calc_global_load(unsigned long ticks);
  47
  48#endif /* _LINUX_SCHED_LOADAVG_H */
  49