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        printf("static const u32 runnable_avg_yN_inv[] = {");
  24        for (i = 0; i < HALFLIFE; i++) {
  25                x = ((1UL<<32)-1)*pow(y, i);
  26
  27                if (i % 6 == 0) printf("\n\t");
  28                printf("0x%8x, ", x);
  29        }
  30        printf("\n};\n\n");
  31}
  32
  33int sum = 1024;
  34
  35void calc_runnable_avg_yN_sum(void)
  36{
  37        int i;
  38
  39        printf("static const u32 runnable_avg_yN_sum[] = {\n\t    0,");
  40        for (i = 1; i <= HALFLIFE; i++) {
  41                if (i == 1)
  42                        sum *= y;
  43                else
  44                        sum = sum*y + 1024*y;
  45
  46                if (i % 11 == 0)
  47                        printf("\n\t");
  48
  49                printf("%5d,", sum);
  50        }
  51        printf("\n};\n\n");
  52}
  53
  54int n = -1;
  55/* first period */
  56long max = 1024;
  57
  58void calc_converged_max(void)
  59{
  60        long last = 0, y_inv = ((1UL<<32)-1)*y;
  61
  62        for (; ; n++) {
  63                if (n > -1)
  64                        max = ((max*y_inv)>>SHIFT) + 1024;
  65                        /*
  66                         * This is the same as:
  67                         * max = max*y + 1024;
  68                         */
  69
  70                if (last == max)
  71                        break;
  72
  73                last = max;
  74        }
  75        n--;
  76        printf("#define LOAD_AVG_PERIOD %d\n", HALFLIFE);
  77        printf("#define LOAD_AVG_MAX %ld\n", max);
  78//      printf("#define LOAD_AVG_MAX_N %d\n\n", n);
  79}
  80
  81void calc_accumulated_sum_32(void)
  82{
  83        int i, x = sum;
  84
  85        printf("static const u32 __accumulated_sum_N32[] = {\n\t     0,");
  86        for (i = 1; i <= n/HALFLIFE+1; i++) {
  87                if (i > 1)
  88                        x = x/2 + sum;
  89
  90                if (i % 6 == 0)
  91                        printf("\n\t");
  92
  93                printf("%6d,", x);
  94        }
  95        printf("\n};\n\n");
  96}
  97
  98void main(void)
  99{
 100        printf("/* Generated by Documentation/scheduler/sched-pelt; do not modify. */\n\n");
 101
 102        y = pow(0.5, 1/(double)HALFLIFE);
 103
 104        calc_runnable_avg_yN_inv();
 105//      calc_runnable_avg_yN_sum();
 106        calc_converged_max();
 107//      calc_accumulated_sum_32();
 108}
 109