Line data    Source code

       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          18 : calc_load(unsigned long load, unsigned long exp, unsigned long active)
      30             : {
      31          18 :         unsigned long newload;
      32             : 
      33          18 :         newload = load * exp + active * (FIXED_1 - exp);
      34          12 :         if (active >= load)
      35          10 :                 newload += FIXED_1-1;
      36             : 
      37          14 :         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(void);
      47             : 
      48             : #endif /* _LINUX_SCHED_LOADAVG_H */