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       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                 :          3 :         newload = load * exp + active * (FIXED_1 - exp);
      34                 :          3 :         if (active >= load)
      35                 :          3 :                 newload += FIXED_1-1;
      36                 :            : 
      37                 :          3 :         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 */