Scheduler pelt c programΒΆ

```/*
* 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--;
}

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();
}
```