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
calc_load(unsigned long load,unsigned long exp,unsigned long active)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(void);
47 
48 #endif /* _LINUX_SCHED_LOADAVG_H */
49