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(void);
47
48#endif /* _LINUX_SCHED_LOADAVG_H */
49