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📁 ..
📄 Makefile.am(4.74 KB)
📄 Makefile.in(49.93 KB)
📄 README(2.13 KB)
📄 audio-pcm.c(3.57 KB)
📄 byteorder.c(839 B)
📄 hist.c(1.94 KB)
📄 invoke-ntp-keygen.menu(55 B)
📄 invoke-ntp-keygen.texi(50.06 KB)
📄 jitter.c(2.73 KB)
📄 kern.c(5.45 KB)
📄 longsize.c(150 B)
📄 ntp-keygen-opts.c(61.04 KB)
📄 ntp-keygen-opts.def(38.96 KB)
📄 ntp-keygen-opts.h(12.77 KB)
📄 ntp-keygen.1ntp-keygenman(45.69 KB)
📄 ntp-keygen.1ntp-keygenmdoc(39.57 KB)
📄 ntp-keygen.c(64.46 KB)
📄 ntp-keygen.html(90.46 KB)
📄 ntp-keygen.man.in(45.69 KB)
📄 ntp-keygen.mdoc.in(39.57 KB)
📄 ntp-keygen.texi(12.96 KB)
📄 ntptime.c(10.27 KB)
📄 pps-api.c(2.3 KB)
📄 precision.c(5.06 KB)
📄 sht.c(6.09 KB)
📄 testrs6000.c(1.28 KB)
📄 tg.c(16.43 KB)
📄 tg2.c(73.01 KB)
📄 tickadj.c(16.02 KB)
📄 timetrim.c(2.65 KB)

Editing: hist.c

/*
 * This program can be used to calibrate the clock reading jitter of a
 * particular CPU and operating system. It first tickles every element
 * of an array, in order to force pages into memory, then repeatedly calls
 * gettimeofday() and, finally, writes out the time values for later
 * analysis. From this you can determine the jitter and if the clock ever
 * runs backwards.
 */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include "ntp_types.h"

#include <stdio.h>
#include <stdlib.h>

#define NBUF 100001		/* size of basic histogram */
#define NSRT 20000		/* size of overflow histogram */
#define NCNT (600 * 1000000)	/* sample interval (us) */

int col (const void *, const void *);

int
main(
	int argc,
	char *argv[]
	)
{
	struct timeval ts, tr, tp;
	struct timezone tzp;
	int i, j, n;
	long t, u, v, w, gtod[NBUF], ovfl[NSRT];

/*
	 * Force pages into memory
	 */
	for (i = 0; i < NBUF; i++)
		gtod[i] = 0;
	for (i = 0; i < NSRT; i++)
		ovfl[i] = 0;

/*
	 * Construct histogram
	 */
	n = 0;
	gettimeofday(&ts, &tzp);
	t = ts.tv_sec * 1000000 + ts.tv_usec;
	v = t;
	while (1) {
		gettimeofday(&tr, &tzp);
		u = tr.tv_sec * 1000000 + tr.tv_usec; 
		if (u - v > NCNT)
			break;
		w = u - t;
		if (w <= 0) {
/*
			printf("error <= 0 %ld %d %d, %d %d\n", w, ts.tv_sec,
			       ts.tv_usec, tr.tv_sec, tr.tv_usec);
*/
		} else if (w > NBUF - 1) {
			ovfl[n] = w;
			if (n < NSRT - 1)
				n++;
		} else {
			gtod[w]++;
		}
		ts = tr;
		t = u;
	}

/*
	 * Write out histogram
	 */
	for (i = 0; i < NBUF - 1; i++) {
		if (gtod[i] > 0)
			printf("%ld %ld\n", i, gtod[i]);
	}
	if (n == 0)
		return;
	qsort(&ovfl, (size_t)n, sizeof(ovfl[0]), col);
	w = 0;
	j = 0;
	for (i = 0; i < n; i++) {
		if (ovfl[i] != w) {
			if (j > 0)
				printf("%ld %ld\n", w, j);
			w = ovfl[i];
			j = 1;
		} else
			j++;
	}
	if (j > 0)
		printf("%ld %ld\n", w, j);
 
	exit(0);
}

int
col(
	const void *vx,
	const void *vy
	)
{
	const long *x = vx;
	const long *y = vy;

return (*x - *y);
}

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Editing: hist.c

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