1 /*
2 * The following program is used to generate the constants for
3 * computing sched averages.
4 *
5 * ==============================================================
6 * C program (compile with -lm)
7 * ==============================================================
8 */
9
10 #include <math.h>
11 #include <stdio.h>
12
13 #define HALFLIFE 32
14 #define SHIFT 32
15
16 double y;
17
calc_runnable_avg_yN_inv(void)18 void calc_runnable_avg_yN_inv(void)
19 {
20 int i;
21 unsigned int x;
22
23 /* To silence -Wunused-but-set-variable warnings. */
24 printf("static const u32 runnable_avg_yN_inv[] __maybe_unused = {");
25 for (i = 0; i < HALFLIFE; i++) {
26 x = ((1UL<<32)-1)*pow(y, i);
27
28 if (i % 6 == 0) printf("\n\t");
29 printf("0x%8x, ", x);
30 }
31 printf("\n};\n\n");
32 }
33
34 int sum = 1024;
35
calc_runnable_avg_yN_sum(void)36 void calc_runnable_avg_yN_sum(void)
37 {
38 int i;
39
40 printf("static const u32 runnable_avg_yN_sum[] = {\n\t 0,");
41 for (i = 1; i <= HALFLIFE; i++) {
42 if (i == 1)
43 sum *= y;
44 else
45 sum = sum*y + 1024*y;
46
47 if (i % 11 == 0)
48 printf("\n\t");
49
50 printf("%5d,", sum);
51 }
52 printf("\n};\n\n");
53 }
54
55 int n = -1;
56 /* first period */
57 long max = 1024;
58
calc_converged_max(void)59 void calc_converged_max(void)
60 {
61 long last = 0, y_inv = ((1UL<<32)-1)*y;
62
63 for (; ; n++) {
64 if (n > -1)
65 max = ((max*y_inv)>>SHIFT) + 1024;
66 /*
67 * This is the same as:
68 * max = max*y + 1024;
69 */
70
71 if (last == max)
72 break;
73
74 last = max;
75 }
76 n--;
77 printf("#define LOAD_AVG_PERIOD %d\n", HALFLIFE);
78 printf("#define LOAD_AVG_MAX %ld\n", max);
79 // printf("#define LOAD_AVG_MAX_N %d\n\n", n);
80 }
81
calc_accumulated_sum_32(void)82 void calc_accumulated_sum_32(void)
83 {
84 int i, x = sum;
85
86 printf("static const u32 __accumulated_sum_N32[] = {\n\t 0,");
87 for (i = 1; i <= n/HALFLIFE+1; i++) {
88 if (i > 1)
89 x = x/2 + sum;
90
91 if (i % 6 == 0)
92 printf("\n\t");
93
94 printf("%6d,", x);
95 }
96 printf("\n};\n\n");
97 }
98
main(void)99 void main(void)
100 {
101 printf("/* Generated by Documentation/scheduler/sched-pelt; do not modify. */\n\n");
102
103 y = pow(0.5, 1/(double)HALFLIFE);
104
105 calc_runnable_avg_yN_inv();
106 // calc_runnable_avg_yN_sum();
107 calc_converged_max();
108 // calc_accumulated_sum_32();
109 }
110