Add more entries to tracking log

Add number of combined sources, remaining offset correction from
previous update and estimated stddev of the combined offset.

chrony.texi.in

@@ -2074,7 +2074,8 @@ An example line (which actually appears as a single line in the file)
 from the tracking log file is shown below.
 
 @example
-2012-02-23 05:40:50 158.152.1.76     3    340.529      1.606  1.046e-03 N
+2012-02-23 05:40:50 158.152.1.76     3    340.529      1.606  1.046e-03 N \
+            4  6.849e-03 -4.670e-04
 @end example
 
 The columns are as follows (the quantities in square brackets are the
@@ -2104,6 +2105,14 @@ system is fast of UTC). [1.046e-3]
 Leap status (@code{N} means normal, @code{+} means that the last minute
 of this month has 61 seconds, @code{-} means that the last minute of the month
 has 59 seconds, @code{?} means the clock is not currently synchronised.) [N]
+@item
+The number of combined sources. [4]
+@item
+The estimated standard deviation of the combined offset (in seconds).
+[6.849e-03]
+@item
+The remaining offset correction from the previous update (in seconds, positive
+means the system clock is slow of UTC). [-4.670e-04]
 @end enumerate
 
 A banner is periodically written to the log file to indicate the

reference.c

@@ -196,7 +196,7 @@ REF_Initialise(void)
   }
 
   logfileid = CNF_GetLogTracking() ? LOG_FileOpen("tracking",
-      "   Date (UTC) Time     IP Address   St   Freq ppm   Skew ppm     Offset L")
+      "   Date (UTC) Time     IP Address   St   Freq ppm   Skew ppm     Offset L Co  Offset sd Rem. corr.")
     : -1;
 
   max_update_skew = fabs(CNF_GetMaxUpdateSkew()) * 1.0e-6;
@@ -646,12 +646,16 @@ update_leap_status(NTP_Leap leap, time_t now)
 /* ================================================== */
 
 static void
-write_log(struct timeval *ref_time, char *ref, int stratum, NTP_Leap leap, double freq, double skew, double offset)
+write_log(struct timeval *ref_time, char *ref, int stratum, NTP_Leap leap,
+    double freq, double skew, double offset, int combined_sources,
+    double offset_sd, double uncorrected_offset)
 {
   const char leap_codes[4] = {'N', '+', '-', '?'};
   if (logfileid != -1) {
-    LOG_FileWrite(logfileid, "%s %-15s %2d %10.3f %10.3f %10.3e %1c",
+    LOG_FileWrite(logfileid, "%s %-15s %2d %10.3f %10.3f %10.3e %1c %2d %10.3e %10.3e",
-            UTI_TimeToLogForm(ref_time->tv_sec), ref, stratum, freq, skew, offset, leap_codes[leap]);
+            UTI_TimeToLogForm(ref_time->tv_sec), ref, stratum, freq, skew,
+            offset, leap_codes[leap], combined_sources, offset_sd,
+            uncorrected_offset);
   }
 }
 
@@ -660,6 +664,7 @@ write_log(struct timeval *ref_time, char *ref, int stratum, NTP_Leap leap, doubl
 void
 REF_SetReference(int stratum,
                  NTP_Leap leap,
+                 int combined_sources,
                  uint32_t ref_id,
                  IPAddr *ref_ip,
                  struct timeval *ref_time,
@@ -682,6 +687,7 @@ REF_SetReference(int stratum,
   double update_interval;
   double elapsed;
   double correction_rate;
+  double uncorrected_offset;
   struct timeval now, raw_now, ev_now, ev_raw_now;
 
   assert(initialised);
@@ -712,7 +718,8 @@ REF_SetReference(int stratum,
 
   /* This is cheaper than calling LCL_CookTime */
   SCH_GetLastEventTime(&ev_now, NULL, &ev_raw_now);
-  UTI_AddDiffToTimeval(&ev_now, &ev_raw_now, &raw_now, &now);
+  UTI_DiffTimevalsToDouble(&uncorrected_offset, &ev_now, &ev_raw_now);
+  UTI_AddDoubleToTimeval(&raw_now, uncorrected_offset, &now);
 
   UTI_DiffTimevalsToDouble(&elapsed, &now, ref_time);
   our_offset = offset + elapsed * frequency;
@@ -813,7 +820,10 @@ REF_SetReference(int stratum,
             our_leap_status,
             abs_freq_ppm,
             1.0e6*our_skew,
-            our_offset);
+            our_offset,
+            combined_sources,
+            offset_sd,
+            uncorrected_offset);
 
   if (drift_file) {
     /* Update drift file at most once per hour */
@@ -858,7 +868,7 @@ REF_SetManualReference
   /* We are not synchronised to an external source, as such.  This is
    only supposed to be used with the local source option, really
    ... */
-  REF_SetReference(0, LEAP_Unsynchronised, manual_refid, NULL,
+  REF_SetReference(0, LEAP_Unsynchronised, 1, manual_refid, NULL,
                    ref_time, offset, 0.0, frequency, skew, 0.0, 0.0);
 }
 
@@ -868,11 +878,14 @@ void
 REF_SetUnsynchronised(void)
 {
   /* Variables required for logging to statistics log */
-  struct timeval now;
+  struct timeval now, now_raw;
+  double uncorrected_offset;
 
   assert(initialised);
 
-  LCL_ReadCookedTime(&now, NULL);
+  /* This is cheaper than calling LCL_CookTime */
+  SCH_GetLastEventTime(&now, NULL, &now_raw);
+  UTI_DiffTimevalsToDouble(&uncorrected_offset, &now, &now_raw);
 
   if (fb_drifts) {
     schedule_fb_drift(&now);
@@ -887,7 +900,10 @@ REF_SetUnsynchronised(void)
             our_leap_status,
             LCL_ReadAbsoluteFrequency(),
             1.0e6*our_skew,
-            0.0);
+            0.0,
+            0,
+            0.0,
+            uncorrected_offset);
 }
 
 /* ================================================== */

reference.h

@@ -105,6 +105,7 @@ extern void REF_SetReference
 (
  int stratum,
  NTP_Leap leap,
+ int combined_sources,
  uint32_t ref_id,
  IPAddr *ref_ip,
  struct timeval *ref_time,

sched.c

@@ -131,8 +131,6 @@ handle_slew(struct timeval *raw,
 void
 SCH_Initialise(void)
 {
-  struct timeval tv;
-
   FD_ZERO(&read_fds);
   n_read_fds = 0;
 
@@ -146,8 +144,10 @@ SCH_Initialise(void)
 
   LCL_AddParameterChangeHandler(handle_slew, NULL);
 
-  LCL_ReadRawTime(&tv);
+  LCL_ReadRawTime(&last_select_ts_raw);
-  srandom(tv.tv_sec << 16 ^ tv.tv_usec);
+  last_select_ts = last_select_ts_raw;
+
+  srandom(last_select_ts.tv_sec << 16 ^ last_select_ts.tv_usec);
 
   initialised = 1;
 }

sources.c

@@ -426,7 +426,7 @@ source_to_string(SRC_Instance inst)
 
 /* ================================================== */
 
-static void
+static int
 combine_sources(int n_sel_sources, struct timeval *ref_time, double *offset,
                 double *offset_sd, double *frequency, double *skew)
 {
@@ -434,11 +434,14 @@ combine_sources(int n_sel_sources, struct timeval *ref_time, double *offset,
   double src_offset, src_offset_sd, src_frequency, src_skew;
   double src_root_delay, src_root_dispersion, elapsed;
   double weight, sum_weight, sum_offset, sum2_offset_sd, sum_frequency, sum_skew;
-  int i, index;
+  int i, index, combined;
+
+  if (n_sel_sources == 1)
+    return 1;
 
   sum_weight = sum_offset = sum2_offset_sd = sum_frequency = sum_skew = 0.0;
 
-  for (i = 0; i < n_sel_sources; i++) {
+  for (i = combined = 0; i < n_sel_sources; i++) {
     index = sel_sources[i];
     SST_GetTrackingData(sources[index]->stats, &src_ref_time,
                         &src_offset, &src_offset_sd,
@@ -477,6 +480,8 @@ combine_sources(int n_sel_sources, struct timeval *ref_time, double *offset,
         (src_offset - *offset) * (src_offset - *offset));
     sum_frequency += weight * src_frequency;
     sum_skew += weight * src_skew;
+
+    combined++;
   }
 
   assert(sum_weight > 0.0);
@@ -489,6 +494,8 @@ combine_sources(int n_sel_sources, struct timeval *ref_time, double *offset,
   LOG(LOGS_INFO, LOGF_Sources, "combined result offset=%e sd=%e freq=%e skew=%e",
       *offset, *offset_sd, *frequency, *skew);
 #endif
+
+  return combined;
 }
 
 /* ================================================== */
@@ -508,7 +515,7 @@ SRC_SelectSource(uint32_t match_refid)
   int n_endpoints, j1, j2;
   double best_lo, best_hi;
   int depth, best_depth;
-  int n_sel_sources;
+  int n_sel_sources, combined;
   double distance, sel_src_distance;
   int stratum, min_stratum;
   struct SelectInfo *si;
@@ -927,13 +934,12 @@ SRC_SelectSource(uint32_t match_refid)
                               &src_frequency, &src_skew,
                               &src_root_delay, &src_root_dispersion);
 
-          if (n_sel_sources > 1) {
+          combined = combine_sources(n_sel_sources, &ref_time, &src_offset,
-            combine_sources(n_sel_sources, &ref_time, &src_offset,
+                                     &src_offset_sd, &src_frequency, &src_skew);
-                &src_offset_sd, &src_frequency, &src_skew);
-          }
 
           REF_SetReference(sources[selected_source_index]->sel_info.stratum,
                            leap_status,
+                           combined,
                            sources[selected_source_index]->ref_id,
                            sources[selected_source_index]->ip_addr,
                            &ref_time,