cregit-Linux how code gets into the kernel

Release 4.17 Documentation/scheduler/sched-pelt.c

/*
 * 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; printf("static const u32 runnable_avg_yN_inv[] = {"); 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"); }

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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"); }

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Yuyang Du76100.00%1100.00%
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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); }

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Yuyang Du86100.00%1100.00%
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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"); }

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Yuyang Du77100.00%1100.00%
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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(); }

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PersonTokensPropCommitsCommitProp
Yuyang Du34100.00%1100.00%
Total34100.00%1100.00%


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Yuyang Du386100.00%1100.00%
Total386100.00%1100.00%
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