From: Harlan Stenn <stenn@ntp.org>
Date: Thu, 9 Jan 2003 01:38:12 +0000 (-0500)
Subject: Cleanup and improvements from Dave Mills.
X-Git-Tag: NTP_4_1_73~7
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=3683ade08c3bf4316918ecbf81b8963c02ddac20;p=thirdparty%2Fntp.git

Cleanup and improvements from Dave Mills.

bk: 3e1cd2846HlLwpCE7ROEz92VWx1zMg
---

diff --git a/include/ntp.h b/include/ntp.h
index e8be8036f8..ae648d2705 100644
--- a/include/ntp.h
+++ b/include/ntp.h
@@ -122,7 +122,7 @@ typedef char s_char;
 #define	NTP_MINCLOCK	3	/* minimum survivors */
 #define	NTP_MAXCLOCK	10	/* maximum candidates */
 #define MAXDISTANCE	1.	/* max root distance */
-#define CLOCK_SGATE	4.	/* popcorn spike gate */
+#define CLOCK_SGATE	3.	/* popcorn spike gate */
 #define HUFFPUFF	900	/* huff-n'-puff sample interval (s) */
 #define HYST		.5	/* anti-clockhop hysteresis */
 #define HYST_TC		.875	/* anti-clockhop hysteresis decay */
diff --git a/ntpd/ntp_loopfilter.c b/ntpd/ntp_loopfilter.c
index 0e4f03eae2..bb2d07c745 100644
--- a/ntpd/ntp_loopfilter.c
+++ b/ntpd/ntp_loopfilter.c
@@ -40,7 +40,7 @@
 #define CLOCK_AVG	4.	/* parameter averaging constant */
 #define CLOCK_MINSEC	256.	/* min FLL update interval (s) */
 #define CLOCK_MINSTEP	900.	/* step-change timeout (s) */
-#define	CLOCK_ALLAN	3000.	/* compromise Allan intercept (s) */
+#define	CLOCK_ALLAN	1500.	/* compromise Allan intercept (s) */
 #define CLOCK_DAY	86400.	/* one day in seconds (s) */
 #define CLOCK_LIMIT	30	/* poll-adjust threshold */
 #define CLOCK_PGATE	4.	/* poll-adjust gate */
@@ -429,24 +429,22 @@ local_clock(
 
 		/*
 		 * We come here in the normal case for linear phase and
-		 * frequency adjustments. If the offset exceeds the
-		 * previous time error estimate by CLOCK_SGATE and the
-		 * interval since the last update is less than twice the
-		 * poll interval, consider the update a popcorn spike
-		 * and ignore it.
+		 * frequency adjustments. If the difference between the
+		 * last offset and the current one exceeds the jitter by
+		 * CLOCK_SGATE (4) and the interval since the last
+		 * update is less than twice the system poll interval,
+		 * consider the update a popcorn spike and ignore it..
 		 */
 		default:
 			allow_panic = FALSE;
-			if (fabs(fp_offset - last_offset) >
-			    CLOCK_SGATE * oerror && mu <
+			dtemp = fabs(fp_offset - last_offset);
+			if (dtemp > CLOCK_SGATE * oerror && mu <
 			    ULOGTOD(sys_poll + 1)) {
 #ifdef DEBUG
 				if (debug)
 					printf(
 				    "local_clock: popcorn %.6f %.6f\n",
-					    fabs(fp_offset -
-					    last_offset), CLOCK_SGATE *
-					    oerror);
+					    dtemp, oerror);
 #endif
 				last_offset = fp_offset;
 				return (0);
@@ -457,22 +455,21 @@ local_clock(
 			 * which depend on the poll interval, update
 			 * interval and Allan intercept. For the FLL,
 			 * the averaging interval is clamped not less
-			 * than the Allan intercept. For the PLL, the
-			 * averaging interval is clamped not greater
+			 * than the Allan intercept and the weight
+			 * proportional to the poll interval from zero
+			 * to unity at the Allan intercept. For the PLL,
+			 * the averaging interval is clamped not greater
 			 * than the poll interval. Particularly for the
 			 * PLL, these measures allow oversampling, but
 			 * not undersampling and insure stability even
 			 * when the rules of fair engagement are broken.
 			 */
+			etemp = min(1, sqrt(mu) / allan_xpt);
 			dtemp = max(mu, allan_xpt);
-			flladj = (fp_offset - clock_offset) /
+			flladj = (fp_offset - clock_offset) * etemp /
 			    (CLOCK_FLL * dtemp);
-
-printf("xxx diff %f d %f\n", (fp_offset - clock_offset) * 1e6,
-    CLOCK_FLL * dtemp);
- 
-			dtemp = 4 * CLOCK_PLL * ULOGTOD(sys_poll);
 			etemp = min(mu, ULOGTOD(sys_poll));
+			dtemp = 4 * CLOCK_PLL * ULOGTOD(sys_poll);
 			plladj = fp_offset * etemp / (dtemp * dtemp);
 			last_time = peer->epoch;
 			last_offset = clock_offset = fp_offset;
@@ -614,10 +611,6 @@ printf("xxx diff %f d %f\n", (fp_offset - clock_offset) * 1e6,
 	 */
 	etemp = clock_frequency + flladj + plladj;
 	drift_comp += etemp;
-
-printf("ofs %f freq %f cf %f pll %f fll %f\n", fp_offset, drift_comp *
-    1e6, clock_frequency * 1e6, plladj * 1e6, flladj * 1e6);
-
 	if (drift_comp > NTP_MAXFREQ)
 		drift_comp = NTP_MAXFREQ;
 	else if (drift_comp <= -NTP_MAXFREQ)
diff --git a/ntpd/ntp_proto.c b/ntpd/ntp_proto.c
index 848c29d406..fa2cea6a35 100644
--- a/ntpd/ntp_proto.c
+++ b/ntpd/ntp_proto.c
@@ -1650,7 +1650,8 @@ clock_filter(
 	 */
 	if (m == 0)
 		return;
-	etemp = peer->offset;
+	etemp = fabs(peer->offset - peer->filter_offset[k]);
+	dtemp = sqrt(peer->jitter);
 	peer->offset = peer->filter_offset[k];
 	peer->delay = peer->filter_delay[k];
 	if (m > 1)
@@ -1677,13 +1678,13 @@ clock_filter(
 	 * the last update is less than twice the system poll interval,
 	 * consider the update a popcorn spike and ignore it.
 	 */
-	if (m > 1 && fabs(peer->offset - etemp) > SQRT(peer->jitter) *
-	    CLOCK_SGATE && peer->filter_epoch[k] - peer->epoch <
-	    (1 << (sys_poll + 1))) {
+	if (m > 1 && etemp > CLOCK_SGATE * dtemp &&
+	    peer->filter_epoch[k] - peer->epoch < (1 << (sys_poll +
+	    1))) {
 #ifdef DEBUG
 		if (debug)
-			printf("clock_filter: n %d popcorn spike %.6f jitter %.6f\n",
-			    m, peer->offset, SQRT(peer->jitter));
+			printf("clock_filter: popcorn %.6f %.6f\n",
+			    etemp, dtemp);
 #endif
 		return;
 	}