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-rw-r--r--contrib/ntp/util/jitter.c108
1 files changed, 87 insertions, 21 deletions
diff --git a/contrib/ntp/util/jitter.c b/contrib/ntp/util/jitter.c
index 462fe12..dda2655 100644
--- a/contrib/ntp/util/jitter.c
+++ b/contrib/ntp/util/jitter.c
@@ -1,16 +1,31 @@
/*
* 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.
+ * of an array, in order to force pages into memory, then repeatedly
+ * reads the system clock 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 <stdio.h>
#include <sys/time.h>
+#include <stdlib.h>
+#include "jitter.h"
+
+#define NBUF 80002
+#define FRAC 4294967296. /* a bbbbillion */
+#define JAN_1970 2208988800UL /* Unix base epoch */
+#define CLOCK_GETTIME /* Solaris hires clock */
-#define NBUF 20002
+int debug;
+char progname[10];
+double sys_residual;
+double average;
+void sys_gettime(l_fp *);
int
main(
@@ -18,11 +33,9 @@ main(
char *argv[]
)
{
- struct timeval ts, tr;
- struct timezone tzp;
- long temp, j, i, gtod[NBUF];
-
- gettimeofday(&ts, &tzp);
+ l_fp tr;
+ int i, j;
+ double dtemp, gtod[NBUF];
/*
* Force pages into memory
@@ -34,19 +47,18 @@ main(
* Construct gtod array
*/
for (i = 0; i < NBUF; i ++) {
- gettimeofday(&tr, &tzp);
- gtod[i] = (tr.tv_sec - ts.tv_sec) * 1000000 + tr.tv_usec;
+ get_systime(&tr);
+ LFPTOD(&tr, gtod[i]);
}
/*
- * Write out gtod array for later processing with S
+ * Write out gtod array for later processing with Matlab
*/
+ average = 0;
for (i = 0; i < NBUF - 2; i++) {
- /*
- printf("%lu\n", gtod[i]);
- */
gtod[i] = gtod[i + 1] - gtod[i];
- printf("%lu\n", gtod[i]);
+ printf("%13.9f\n", gtod[i]);
+ average += gtod[i];
}
/*
@@ -55,17 +67,71 @@ main(
for (i = 0; i < NBUF - 2; i++) {
for (j = 0; j <= i; j++) {
if (gtod[j] > gtod[i]) {
- temp = gtod[j];
+ dtemp = gtod[j];
gtod[j] = gtod[i];
- gtod[i] = temp;
+ gtod[i] = dtemp;
}
}
}
+ average = average / (NBUF - 2);
+ fprintf(stderr, "Average %13.9f\n", average);
fprintf(stderr, "First rank\n");
for (i = 0; i < 10; i++)
- fprintf(stderr, "%10ld%10ld\n", i, gtod[i]);
+ fprintf(stderr, "%2d %13.9f\n", i, gtod[i]);
fprintf(stderr, "Last rank\n");
for (i = NBUF - 12; i < NBUF - 2; i++)
- fprintf(stderr, "%10ld%10ld\n", i, gtod[i]);
+ fprintf(stderr, "%2d %13.9f\n", i, gtod[i]);
exit(0);
}
+
+
+/*
+ * get_systime - return system time in NTP timestamp format.
+ */
+void
+get_systime(
+ l_fp *now /* system time */
+ )
+{
+ double dtemp;
+
+#if defined(HAVE_CLOCK_GETTIME) || defined(HAVE_GETCLOCK)
+ struct timespec ts; /* seconds and nanoseconds */
+
+ /*
+ * Convert Unix clock from seconds and nanoseconds to seconds.
+ */
+# ifdef HAVE_CLOCK_GETTIME
+ clock_gettime(CLOCK_REALTIME, &ts);
+# else
+ getclock(TIMEOFDAY, &ts);
+# endif
+ now->l_i = ts.tv_sec + JAN_1970;
+ dtemp = ts.tv_nsec / 1e9;
+
+#else /* HAVE_CLOCK_GETTIME || HAVE_GETCLOCK */
+ struct timeval tv; /* seconds and microseconds */
+
+ /*
+ * Convert Unix clock from seconds and microseconds to seconds.
+ */
+ gettimeofday(&tv, NULL);
+ now->l_i = tv.tv_sec + JAN_1970;
+ dtemp = tv.tv_usec / 1e6;
+
+#endif /* HAVE_CLOCK_GETTIME || HAVE_GETCLOCK */
+
+ /*
+ * Renormalize to seconds past 1900 and fraction.
+ */
+ dtemp += sys_residual;
+ if (dtemp >= 1) {
+ dtemp -= 1;
+ now->l_i++;
+ } else if (dtemp < -1) {
+ dtemp += 1;
+ now->l_i--;
+ }
+ dtemp *= FRAC;
+ now->l_uf = (u_int32)dtemp;
+}
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