src/basic/linux/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 /*
  26  * a1 = a0 * e + a * (1 - e)
  27  */
  28 static inline unsigned long
  29 calc_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
  40 extern 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
  46 extern void calc_global_load(unsigned long ticks);
  47
  48 #endif /* _LINUX_SCHED_LOADAVG_H */