LXR linux/Documentation/scheduler/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}
 110