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)
29 printf("\n\t");
30 printf("0x%8x, ", x);
31 }
32 printf("\n};\n\n");
33 }
34
35 int sum = 1024;
36
calc_runnable_avg_yN_sum(void)37 void calc_runnable_avg_yN_sum(void)
38 {
39 int i;
40
41 printf("static const u32 runnable_avg_yN_sum[] = {\n\t 0,");
42 for (i = 1; i <= HALFLIFE; i++) {
43 if (i == 1)
44 sum *= y;
45 else
46 sum = sum*y + 1024*y;
47
48 if (i % 11 == 0)
49 printf("\n\t");
50
51 printf("%5d,", sum);
52 }
53 printf("\n};\n\n");
54 }
55
56 int n = -1;
57 /* first period */
58 long max = 1024;
59
calc_converged_max(void)60 void calc_converged_max(void)
61 {
62 long last = 0, y_inv = ((1UL<<32)-1)*y;
63
64 for (; ; n++) {
65 if (n > -1)
66 max = ((max*y_inv)>>SHIFT) + 1024;
67 /*
68 * This is the same as:
69 * max = max*y + 1024;
70 */
71
72 if (last == max)
73 break;
74
75 last = max;
76 }
77 n--;
78 printf("#define LOAD_AVG_PERIOD %d\n", HALFLIFE);
79 printf("#define LOAD_AVG_MAX %ld\n", max);
80 // printf("#define LOAD_AVG_MAX_N %d\n\n", n);
81 }
82
calc_accumulated_sum_32(void)83 void calc_accumulated_sum_32(void)
84 {
85 int i, x = sum;
86
87 printf("static const u32 __accumulated_sum_N32[] = {\n\t 0,");
88 for (i = 1; i <= n/HALFLIFE+1; i++) {
89 if (i > 1)
90 x = x/2 + sum;
91
92 if (i % 6 == 0)
93 printf("\n\t");
94
95 printf("%6d,", x);
96 }
97 printf("\n};\n\n");
98 }
99
main(void)100 void main(void)
101 {
102 printf("/* Generated by Documentation/scheduler/sched-pelt; do not modify. */\n\n");
103
104 y = pow(0.5, 1/(double)HALFLIFE);
105
106 calc_runnable_avg_yN_inv();
107 // calc_runnable_avg_yN_sum();
108 calc_converged_max();
109 // calc_accumulated_sum_32();
110 }
111