[Bug 3653] Refclock jitter RMS calculation

bk: 5e898e75haMho1ftlNA7fybtoiFkow

diff --git a/ChangeLog b/ChangeLog
index 35d5d36c2faf434a0bbc79ed85afe3473cc63039..853f8657de1a93ef2a27130f1f6823a76e93822c 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+---
+* [Bug 3653] Refclock jitter RMS calculation <perlinger@ntp.org>
+  - thanks to Gerry Garvey
+
 ---
 (4.2.8p14) 2020/03/03 Released by Harlan Stenn <stenn@ntp.org>
 

diff --git a/ntpd/ntp_refclock.c b/ntpd/ntp_refclock.c
index 6a0861ed03bcb91df2087607f0ffcf9c8e87b423..872f4a05263f1b916129c8176d9b842d16342520 100644 (file)
--- a/ntpd/ntp_refclock.c
+++ b/ntpd/ntp_refclock.c
@@ -48,15 +48,15 @@
  * structure, which contains for most drivers the decimal equivalants
  * of the year, day, month, hour, second and millisecond/microsecond
  * decoded from the ASCII timecode.  Additional information includes
- * the receive timestamp, exception report, statistics tallies, etc. 
+ * the receive timestamp, exception report, statistics tallies, etc.
  * In addition, there may be a driver-specific unit structure used for
  * local control of the device.
  *
  * The support routines are passed a pointer to the peer structure,
  * which is used for all peer-specific processing and contains a
  * pointer to the refclockproc structure, which in turn contains a
- * pointer to the unit structure, if used.  The peer structure is 
- * identified by an interface address in the dotted quad form 
+ * pointer to the unit structure, if used.  The peer structure is
+ * identified by an interface address in the dotted quad form
  * 127.127.t.u, where t is the clock type and u the unit.
  */
 #define FUDGEFAC       .1      /* fudge correction factor */
@@ -343,7 +343,7 @@ refclock_timer(
        if (pp->action != NULL && pp->nextaction <= current_time)
                (*pp->action)(p);
 }
-       
+
 
 /*
  * refclock_transmit - simulate the transmit procedure
@@ -435,17 +435,17 @@ refclock_samples_avail(
        )
 {
        u_int   na;
-       
+
 #   if MAXSTAGE & (MAXSTAGE - 1)
-       
+
        na = pp->coderecv - pp->codeproc;
        if (na > MAXSTAGE)
                na += MAXSTAGE;
-       
+
 #   else
-       
+
        na = (pp->coderecv - pp->codeproc) & (MAXSTAGE - 1);
-       
+
 #   endif
        return na;
 }
@@ -462,26 +462,26 @@ refclock_samples_expire(
        )
 {
        u_int   na;
-       
+
        if (nd <= 0)
                return 0;
 
 #   if MAXSTAGE & (MAXSTAGE - 1)
-       
+
        na = pp->coderecv - pp->codeproc;
        if (na > MAXSTAGE)
                na += MAXSTAGE;
        if ((u_int)nd < na)
-               nd = na;        
+               nd = na;
        pp->codeproc = (pp->codeproc + nd) % MAXSTAGE;
-       
+
 #   else
-       
+
        na = (pp->coderecv - pp->codeproc) & (MAXSTAGE - 1);
        if ((u_int)nd > na)
                nd = (int)na;
        pp->codeproc = (pp->codeproc + nd) & (MAXSTAGE - 1);
-       
+
 #   endif
        return nd;
 }
@@ -615,14 +615,14 @@ refclock_sample(
        /*
         * Determine the offset and jitter.
         */
-       pp->offset = 0;
+       pp->offset = off[i];
        pp->jitter = 0;
-       for (k = i; k < j; k++) {
+       for (k = i + 1; k < j; k++) {
                pp->offset += off[k];
-               if (k > i)
-                       pp->jitter += SQUARE(off[k] - off[k - 1]);
+               pp->jitter += SQUARE(off[k] - off[k - 1]);
        }
        pp->offset /= m;
+       m -= (m > 1);   /* only (m-1) terms attribute to jitter! */
        pp->jitter = max(SQRT(pp->jitter / m), LOGTOD(sys_precision));
 
        /*
@@ -736,7 +736,7 @@ refclock_gtlin(
 
        while (sp != spend && dp != dpend) {
                char c;
-               
+
                c = *sp++ & 0x7f;
                if (c >= 0x20 && c < 0x7f)
                        *dp++ = c;
@@ -1407,7 +1407,7 @@ refclock_params(
                    ap->pps_params.mode & ~PPS_TSFMT_TSPEC,
                    PPS_TSFMT_TSPEC) < 0)
                {
-                       if (errno != EOPNOTSUPP) { 
+                       if (errno != EOPNOTSUPP) {
                                msyslog(LOG_ERR,
                                        "refclock_params: time_pps_kcbind: %m");
                                return (0);
@@ -1431,7 +1431,7 @@ int
 refclock_pps(
        struct peer *peer,              /* peer structure pointer */
        struct refclock_atom *ap,       /* atom structure pointer */
-       int     mode                    /* mode bits */ 
+       int     mode                    /* mode bits */
        )
 {
        struct refclockproc *pp;
@@ -1443,7 +1443,7 @@ refclock_pps(
         * We require the clock to be synchronized before setting the
         * parameters. When the parameters have been set, fetch the
         * most recent PPS timestamp.
-        */ 
+        */
        pp = peer->procptr;
        if (ap->handle == 0)
                return (0);
@@ -1519,7 +1519,7 @@ refclock_pps(
        pp->lastrec.l_uf = (u_int32)(dtemp * FRAC);
        clk_add_sample(pp, dcorr);
        refclock_checkburst(peer, pp);
-       
+
 #ifdef DEBUG
        if (debug > 1)
                printf("refclock_pps: %lu %f %f\n", current_time,
@@ -1579,7 +1579,7 @@ refclock_ppsaugment(
        )
 {
        l_fp            delta[1];
-       
+
 #ifdef HAVE_PPSAPI
 
        pps_info_t      pps_info;
@@ -1589,14 +1589,14 @@ refclock_ppsaugment(
 
        static const uint32_t s_plim_hi = UINT32_C(1932735284);
        static const uint32_t s_plim_lo = UINT32_C(2362232013);
-       
+
        /* fixup receive time in case we have to bail out early */
        DTOLFP(rcvfudge, delta);
        L_SUB(rcvtime, delta);
 
        if (NULL == ap)
                return FALSE;
-       
+
        ZERO(timeout);
        ZERO(pps_info);
 
@@ -1630,7 +1630,7 @@ refclock_ppsaugment(
        phase = delta->l_ui;
        if (phase >= 2 && phase < (uint32_t)-2)
                return FALSE; /* PPS is stale, don't use it */
-       
+
        /* If the phase is too close to 0.5, the decision whether to
         * move up or down is becoming noise sensitive. That is, we
         * might amplify usec noise between samples into seconds with a
@@ -1642,7 +1642,7 @@ refclock_ppsaugment(
        phase = delta->l_uf;
        if (phase > s_plim_hi && phase < s_plim_lo)
                return FALSE; /* we're in the noise lock gap */
-       
+
        /* sign-extend fraction into seconds */
        delta->l_ui = UINT32_C(0) - ((phase >> 31) & 1);
        /* add it up now */
@@ -1650,7 +1650,7 @@ refclock_ppsaugment(
        return TRUE;
 
 #   else /* have no PPS support at all */
-       
+
        /* just fixup receive time and fail */
        UNUSED_ARG(ap);
        UNUSED_ARG(ppsfudge);
@@ -1658,7 +1658,7 @@ refclock_ppsaugment(
        DTOLFP(rcvfudge, delta);
        L_SUB(rcvtime, delta);
        return FALSE;
-       
+
 #   endif
 }
 
@@ -1694,7 +1694,7 @@ refclock_checkburst(
         * reach mask.  With less samples available, we break away.
         */
        needs  = peer->reach;
-       needs -= (needs >> 1) & 0x55; 
+       needs -= (needs >> 1) & 0x55;
        needs  = (needs & 0x33) + ((needs >> 2) & 0x33);
        needs  = (needs + (needs >> 4)) & 0x0F;
        if (needs > 6)
@@ -1706,7 +1706,7 @@ refclock_checkburst(
 
        /* Get serious. Reduce the poll to minimum and schedule early.
         * (Changing the peer poll is probably in vain, as it will be
-        * re-adjusted, but maybe some time the hint will work...) 
+        * re-adjusted, but maybe some time the hint will work...)
         */
        peer->hpoll = peer->minpoll;
        peer->nextdate = limit;
@@ -1749,7 +1749,7 @@ refclock_vformat_lcode(
                len = 0;
        else if (len >= sizeof(pp->a_lastcode))
                len = sizeof(pp->a_lastcode) - 1;
-       
+
        pp->lencode = (u_short)len;
        pp->a_lastcode[len] = '\0';
        /* !note! the NUL byte is needed in case vsnprintf() really fails */
@@ -1763,10 +1763,10 @@ refclock_format_lcode(
        )
 {
        va_list va;
-       
+
        va_start(va, fmt);
        refclock_vformat_lcode(pp, fmt, va);
-       va_end(va);     
+       va_end(va);
 }
 
 #endif /* REFCLOCK */