More initial convergence improvements from Dave Mills

bk: 4c96d6fegy3UdAaIPl9vESF2TWx1rg

diff --git a/ChangeLog b/ChangeLog
index fceaebd6f452de350faa4efde98059d8782e968c..d76d2a3d0ab5441191bb3f6ef21f883df3a9c919 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,4 @@
+* More Initial convergence improvements from Dave Mills.
 (4.2.7p52) 2010/09/19 Released by Harlan Stenn <stenn@ntp.org>
 * Initial convergence improvements from Dave Mills.
 (4.2.7p51) 2010/09/18 Released by Harlan Stenn <stenn@ntp.org>

diff --git a/ntpd/ntp_loopfilter.c b/ntpd/ntp_loopfilter.c
index fc2ce43c183d61ec7a0c6c09108f69092ac70bc0..ab0971ae7a732a2192881c5aa9e6006a3044a41d 100644 (file)
--- a/ntpd/ntp_loopfilter.c
+++ b/ntpd/ntp_loopfilter.c
@@ -37,6 +37,7 @@
 #define CLOCK_PLL      16.     /* PLL loop gain (log2) */
 #define CLOCK_AVG      8.      /* parameter averaging constant */
 #define CLOCK_FLL      .25     /* FLL loop gain */
+#define        CLOCK_FLOOR     .0005   /* startup offset floor (s) */
 #define        CLOCK_ALLAN     11      /* Allan intercept (log2 s) */
 #define CLOCK_DAY      86400.  /* one day in seconds (s) */
 #define CLOCK_JUNE     (CLOCK_DAY * 30) /* June in seconds (s) */
@@ -142,7 +143,7 @@ int ext_enable;             /* external clock enabled */
 int    pps_stratum;            /* pps stratum */
 int    allow_panic = FALSE;    /* allow panic correction */
 int    mode_ntpdate = FALSE;   /* exit on first clock set */
-int    freqcnt;                /* initial frequency clamp */
+int    freq_cnt;               /* initial frequency clamp */
 
 /*
  * Clock state machine variables
@@ -416,6 +417,7 @@ local_clock(
                 * the stepout threshold.
                 */
                case EVNT_NSET:
+                       freq_cnt = clock_minstep;
                        rstclock(EVNT_FREQ, fp_offset);
                        break;
 
@@ -426,7 +428,7 @@ local_clock(
                 * counter decrements to zero.
                 */
                case EVNT_FSET:
-                       freqcnt = clock_minstep;
+                       freq_cnt = clock_minstep;
                        rstclock(EVNT_SYNC, fp_offset);
                        break;
 
@@ -441,10 +443,9 @@ local_clock(
                                return (0);
 
                        clock_frequency = direct_freq(fp_offset);
-                       freqcnt = clock_minstep;
+                       freq_cnt = clock_minstep;
                        rstclock(EVNT_SYNC, 0);
-                       break;
-
+                       /* fall through to default */
 
                /*
                 * We get here by default in SYNC and SPIK states. Here
@@ -454,7 +455,7 @@ local_clock(
                 */
                default:
                        allow_panic = FALSE;
-                       if (freqcnt == 0) {
+                       if (freq_cnt == 0) {
 
                                /*
                                 * The FLL and PLL frequency gain constants
@@ -501,7 +502,7 @@ local_clock(
         * lead to overflow problems. This might occur if some misguided
         * lad set the step threshold to something ridiculous.
         */
-       if (pll_control && kern_enable && freqcnt == 0) {
+       if (pll_control && kern_enable && freq_cnt == 0) {
 
                /*
                 * We initialize the structure for the ntp_adjtime()
@@ -638,7 +639,7 @@ local_clock(
         * helps calm the dance. Works best using burst mode. Don't
         * fiddle with the poll during the startup clamp period.
         */
-       if (freqcnt > 0) {
+       if (freq_cnt > 0) {
                tc_counter = 0;
        } else if (fabs(clock_offset) < CLOCK_PGATE * clock_jitter) {
                tc_counter += sys_poll;
@@ -705,8 +706,10 @@ adj_host_clock(
         * time constant is clamkped at 2.
         */
        sys_rootdisp += clock_phi;
-       if (freqcnt > 0)
-               freqcnt--;
+       if (fabs(clock_offset) < CLOCK_FLOOR)
+               freq_cnt = 0;
+       else if (freq_cnt > 0)
+               freq_cnt--;
 
 #ifndef LOCKCLOCK
        /*
@@ -714,7 +717,7 @@ adj_host_clock(
         * get out of Dodge quick.
         */
        if (!ntp_enable || mode_ntpdate || (pll_control &&
-           kern_enable && freqcnt == 0))
+           kern_enable && freq_cnt == 0))
                return;
 
        /*
@@ -723,7 +726,7 @@ adj_host_clock(
         * dominated by the FLL above the Allan intercept. Note the
         * reduced time constant at startup.
         */
-       if (freqcnt > 0)
+       if (freq_cnt > 0)
                adjustment = clock_offset / (CLOCK_PLL * 4);
        else
                adjustment = clock_offset / (CLOCK_PLL * ULOGTOD(sys_poll));