Scheduler pelt c program 【ChatGPT】

/*
 * The following program is used to generate the constants for
 * computing sched averages.
 *
 * ==============================================================
 *    C program (compile with -lm)
 * ==============================================================
 */
#include <math.h>
#include <stdio.h>
#define HALFLIFE 32
#define SHIFT 32
double y;
void calc_runnable_avg_yN_inv(void)
{
  int i;
  unsigned int x;
  /* To silence -Wunused-but-set-variable warnings. */
  printf("static const u32 runnable_avg_yN_inv[] __maybe_unused = {");
  for (i = 0; i < HALFLIFE; i++) {
    x = ((1UL<<32)-1)*pow(y, i);
    if (i % 6 == 0) printf("\n\t");
    printf("0x%8x, ", x);
  }
  printf("\n};\n\n");
}
int sum = 1024;
void calc_runnable_avg_yN_sum(void)
{
  int i;
  printf("static const u32 runnable_avg_yN_sum[] = {\n\t    0,");
  for (i = 1; i <= HALFLIFE; i++) {
    if (i == 1)
      sum *= y;
    else
      sum = sum*y + 1024*y;
    if (i % 11 == 0)
      printf("\n\t");
    printf("%5d,", sum);
  }
  printf("\n};\n\n");
}
int n = -1;
/* first period */
long max = 1024;
void calc_converged_max(void)
{
  long last = 0, y_inv = ((1UL<<32)-1)*y;
  for (; ; n++) {
    if (n > -1)
      max = ((max*y_inv)>>SHIFT) + 1024;
      /*
       * This is the same as:
       * max = max*y + 1024;
       */
    if (last == max)
      break;
    last = max;
  }
  n--;
  printf("#define LOAD_AVG_PERIOD %d\n", HALFLIFE);
  printf("#define LOAD_AVG_MAX %ld\n", max);
//  printf("#define LOAD_AVG_MAX_N %d\n\n", n);
}
void calc_accumulated_sum_32(void)
{
  int i, x = sum;
  printf("static const u32 __accumulated_sum_N32[] = {\n\t     0,");
  for (i = 1; i <= n/HALFLIFE+1; i++) {
    if (i > 1)
      x = x/2 + sum;
    if (i % 6 == 0)
      printf("\n\t");
    printf("%6d,", x);
  }
  printf("\n};\n\n");
}
void main(void)
{
  printf("/* Generated by Documentation/scheduler/sched-pelt; do not modify. */\n\n");
  y = pow(0.5, 1/(double)HALFLIFE);
  calc_runnable_avg_yN_inv();
//  calc_runnable_avg_yN_sum();
  calc_converged_max();
//  calc_accumulated_sum_32();
}