sched-pelt.c

  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
 16double y;
 17
 18void 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
 34int sum = 1024;
 35
 36void 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
 55int n = -1;
 56/* first period */
 57long max = 1024;
 58
 59void 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
 82void 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
 99void 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}