sources: allow setting minsamples and maxsamples for each source

The minsamples and maxsamples directives now set the default value,
which can be overriden for individual sources in the server/peer/pool
and refclock directives.

chrony.texi.in

@@ -2375,9 +2375,11 @@ crystal oscillator.
 @c {{{ maxsamples
 @node maxsamples directive
 @subsection maxsamples
-The @code{maxsamples} directive sets the maximum number of samples
+The @code{maxsamples} directive sets the default maximum number of samples
-@code{chronyd} should keep for each source. The default is 0, which
+@code{chronyd} should keep for each source.  This setting can be overriden for
-disables the configurable limit, and the useful range is 4 to 64.
+individual sources in the @code{server} and @code{refclock} directives
+(@pxref{server directive}, @pxref{refclock directive}).  The default value is
+0, which disables the configurable limit.  The useful range is 4 to 64.
 
 The syntax is
 
@@ -2439,9 +2441,11 @@ the new master estimate.
 @c {{{ minsamples
 @node minsamples directive
 @subsection minsamples
-The @code{minsamples} directive sets the minimum number of samples
+The @code{minsamples} directive sets the default minimum number of samples
-@code{chronyd} should try to keep for each source. The default is 0 and the
+@code{chronyd} should keep for each source.  This setting can be overriden for
-useful range is 4 to 64.
+individual sources in the @code{server} and @code{refclock} directives
+(@pxref{server directive}, @pxref{refclock directive}).  The default value is
+0.  The useful range is 4 to 64.
 
 The syntax is
 
@@ -2669,6 +2673,12 @@ Prefer this source over sources without prefer option.
 @item noselect
 Never select this source.  This is useful for monitoring or with sources
 which are not very accurate, but are locked with a PPS refclock.
+@item minsamples
+Set the minimum number of samples kept for this source.  This overrides the
+@code{minsamples} directive (@pxref{minsamples directive}).
+@item maxsamples
+Set the maximum number of samples kept for this source.  This overrides the
+@code{maxsamples} directive (@pxref{maxsamples directive}).
 @end table
 
 @c }}}
@@ -2956,6 +2966,14 @@ Prefer this source over sources without prefer option.
 @item noselect
 Never select this source.  This is particularly useful for monitoring.
 
+@item minsamples
+Set the minimum number of samples kept for this source.  This overrides the
+@code{minsamples} directive (@pxref{minsamples directive}).
+
+@item maxsamples
+Set the maximum number of samples kept for this source.  This overrides the
+@code{maxsamples} directive (@pxref{maxsamples directive}).
+
 @end table
 @c }}}
 @c {{{ stratumweight

client.c

@@ -965,6 +965,16 @@ process_cmd_add_server_or_peer(CMD_Request *msg, char *line)
         break;
       }
 
+      if (data.params.min_samples != SRC_DEFAULT_MINSAMPLES) {
+        fprintf(stderr, "Option minsamples not supported\n");
+        break;
+      }
+
+      if (data.params.max_samples != SRC_DEFAULT_MAXSAMPLES) {
+        fprintf(stderr, "Option maxsamples not supported\n");
+        break;
+      }
+
       msg->data.ntp_source.port = htonl((unsigned long) data.port);
       UTI_IPHostToNetwork(&ip_addr, &msg->data.ntp_source.ip_addr);
       msg->data.ntp_source.minpoll = htonl(data.params.minpoll);
@@ -1024,6 +1034,12 @@ process_cmd_add_server_or_peer(CMD_Request *msg, char *line)
     case CPS_BadMaxsources:
       fprintf(stderr, "Unreadable maxsources value\n");
       break;
+    case CPS_BadMinsamples:
+      fprintf(stderr, "Unreadable minsamples value\n");
+      break;
+    case CPS_BadMaxsamples:
+      fprintf(stderr, "Unreadable maxsamples value\n");
+      break;
   }
 
   return result;

cmdparse.c

@@ -61,6 +61,8 @@ CPS_ParseNTPSourceAdd(char *line, CPS_NTP_Source *src)
   src->params.poll_target = SRC_DEFAULT_POLLTARGET;
   src->params.version = NTP_VERSION;
   src->params.max_sources = SRC_DEFAULT_MAXSOURCES;
+  src->params.min_samples = SRC_DEFAULT_MINSAMPLES;
+  src->params.max_samples = SRC_DEFAULT_MAXSAMPLES;
   src->params.sel_option = SRC_SelectNormal;
 
   result = CPS_Success;
@@ -184,6 +186,22 @@ CPS_ParseNTPSourceAdd(char *line, CPS_NTP_Source *src)
             line += n;
           }
 
+        } else if (!strcasecmp(cmd, "minsamples")) {
+          if (sscanf(line, "%d%n", &src->params.min_samples, &n) != 1) {
+            result = CPS_BadMinsamples;
+            done = 1;
+          } else {
+            line += n;
+          }
+
+        } else if (!strcasecmp(cmd, "maxsamples")) {
+          if (sscanf(line, "%d%n", &src->params.max_samples, &n) != 1) {
+            result = CPS_BadMaxsamples;
+            done = 1;
+          } else {
+            line += n;
+          }
+
         } else {
           result = CPS_BadOption;
           done = 1;

cmdparse.h

@@ -46,6 +46,8 @@ typedef enum {
   CPS_BadPolltarget,
   CPS_BadVersion,
   CPS_BadMaxsources,
+  CPS_BadMinsamples,
+  CPS_BadMaxsamples,
 } CPS_Status;
 
 typedef struct {

conf.c

@@ -635,6 +635,12 @@ parse_source(char *line, NTP_Source_Type type, int pool)
     case CPS_BadMaxsources:
       other_parse_error("Unreadable maxsources");
       break;
+    case CPS_BadMinsamples:
+      other_parse_error("Unreadable minsamples");
+      break;
+    case CPS_BadMaxsamples:
+      other_parse_error("Unreadable maxsamples");
+      break;
   }
 }
 
@@ -667,7 +673,7 @@ parse_pool(char *line)
 static void
 parse_refclock(char *line)
 {
-  int n, poll, dpoll, filter_length, pps_rate;
+  int n, poll, dpoll, filter_length, pps_rate, min_samples, max_samples;
   uint32_t ref_id, lock_ref_id;
   double offset, delay, precision, max_dispersion;
   char *p, *cmd, *name, *param;
@@ -679,6 +685,8 @@ parse_refclock(char *line)
   dpoll = 0;
   filter_length = 64;
   pps_rate = 0;
+  min_samples = SRC_DEFAULT_MINSAMPLES;
+  max_samples = SRC_DEFAULT_MAXSAMPLES;
   offset = 0.0;
   delay = 1e-9;
   precision = 0.0;
@@ -732,6 +740,12 @@ parse_refclock(char *line)
     } else if (!strcasecmp(cmd, "rate")) {
       if (sscanf(line, "%d%n", &pps_rate, &n) != 1)
         break;
+    } else if (!strcasecmp(cmd, "minsamples")) {
+      if (sscanf(line, "%d%n", &min_samples, &n) != 1)
+        break;
+    } else if (!strcasecmp(cmd, "maxsamples")) {
+      if (sscanf(line, "%d%n", &max_samples, &n) != 1)
+        break;
     } else if (!strcasecmp(cmd, "offset")) {
       if (sscanf(line, "%lf%n", &offset, &n) != 1)
         break;
@@ -768,6 +782,8 @@ parse_refclock(char *line)
   refclock->poll = poll;
   refclock->filter_length = filter_length;
   refclock->pps_rate = pps_rate;
+  refclock->min_samples = min_samples;
+  refclock->max_samples = max_samples;
   refclock->offset = offset;
   refclock->delay = delay;
   refclock->precision = precision;

ntp_core.c

@@ -461,7 +461,10 @@ NCR_GetInstance(NTP_Remote_Address *remote_addr, NTP_Source_Type type, SourcePar
   }
 
   /* Create a source instance for this NTP source */
-  result->source = SRC_CreateNewInstance(UTI_IPToRefid(&remote_addr->ip_addr), SRC_NTP, params->sel_option, &result->remote_addr.ip_addr);
+  result->source = SRC_CreateNewInstance(UTI_IPToRefid(&remote_addr->ip_addr),
+                                         SRC_NTP, params->sel_option,
+                                         &result->remote_addr.ip_addr,
+                                         params->min_samples, params->max_samples);
 
   result->timer_running = 0;
   result->timeout_id = 0;

refclock.c

@@ -260,7 +260,8 @@ RCL_AddRefclock(RefclockParameters *params)
 
   filter_init(&inst->filter, params->filter_length, params->max_dispersion);
 
-  inst->source = SRC_CreateNewInstance(inst->ref_id, SRC_REFCLOCK, params->sel_option, NULL);
+  inst->source = SRC_CreateNewInstance(inst->ref_id, SRC_REFCLOCK, params->sel_option, NULL,
+                                       params->min_samples, params->max_samples);
 
   DEBUG_LOG(LOGF_Refclock, "refclock %s refid=%s poll=%d dpoll=%d filter=%d",
       params->driver_name, UTI_RefidToString(inst->ref_id),

refclock.h

@@ -38,6 +38,8 @@ typedef struct {
   int poll;
   int filter_length;
   int pps_rate;
+  int min_samples;
+  int max_samples;
   uint32_t ref_id;
   uint32_t lock_ref_id;
   double offset;

sources.c

@@ -207,14 +207,19 @@ void SRC_Finalise(void)
 /* Function to create a new instance.  This would be called by one of
    the individual source-type instance creation routines. */
 
-SRC_Instance SRC_CreateNewInstance(uint32_t ref_id, SRC_Type type, SRC_SelectOption sel_option, IPAddr *addr)
+SRC_Instance SRC_CreateNewInstance(uint32_t ref_id, SRC_Type type, SRC_SelectOption sel_option, IPAddr *addr, int min_samples, int max_samples)
 {
   SRC_Instance result;
 
   assert(initialised);
 
+  if (min_samples == SRC_DEFAULT_MINSAMPLES)
+    min_samples = CNF_GetMinSamples();
+  if (max_samples == SRC_DEFAULT_MAXSAMPLES)
+    max_samples = CNF_GetMaxSamples();
+
   result = MallocNew(struct SRC_Instance_Record);
-  result->stats = SST_CreateInstance(ref_id, addr);
+  result->stats = SST_CreateInstance(ref_id, addr, min_samples, max_samples);
 
   if (n_sources == max_n_sources) {
     /* Reallocate memory */

sources.h

@@ -65,7 +65,7 @@ typedef enum {
 /* Function to create a new instance.  This would be called by one of
    the individual source-type instance creation routines. */
 
-extern SRC_Instance SRC_CreateNewInstance(uint32_t ref_id, SRC_Type type, SRC_SelectOption sel_option, IPAddr *addr);
+extern SRC_Instance SRC_CreateNewInstance(uint32_t ref_id, SRC_Type type, SRC_SelectOption sel_option, IPAddr *addr, int min_samples, int max_samples);
 
 /* Function to get rid of a source when it is being unconfigured.
    This may cause the current reference source to be reselected, if this

sourcestats.c

@@ -43,10 +43,6 @@
    to store per source */
 #define MAX_SAMPLES 64
 
-/* User defined maximum and minimum number of samples */
-int max_samples;
-int min_samples;
-
 /* This is the assumed worst case bound on an unknown frequency,
    2000ppm, which would be pretty bad */
 #define WORST_CASE_FREQ_BOUND (2000.0/1.0e6)
@@ -68,6 +64,10 @@ struct SST_Stats_Record {
   uint32_t refid;
   IPAddr *ip_addr;
 
+  /* User defined minimum and maximum number of samples */
+  int min_samples;
+  int max_samples;
+
   /* Number of samples currently stored.  The samples are stored in circular
      buffer. */
   int n_samples;
@@ -163,8 +163,6 @@ SST_Initialise(void)
   logfileid = CNF_GetLogStatistics() ? LOG_FileOpen("statistics",
       "   Date (UTC) Time     IP Address    Std dev'n Est offset  Offset sd  Diff freq   Est skew  Stress  Ns  Bs  Nr")
     : -1;
-  max_samples = CNF_GetMaxSamples();
-  min_samples = CNF_GetMinSamples();
 }
 
 /* ================================================== */
@@ -178,11 +176,14 @@ SST_Finalise(void)
 /* This function creates a new instance of the statistics handler */
 
 SST_Stats
-SST_CreateInstance(uint32_t refid, IPAddr *addr)
+SST_CreateInstance(uint32_t refid, IPAddr *addr, int min_samples, int max_samples)
 {
   SST_Stats inst;
   inst = MallocNew(struct SST_Stats_Record);
 
+  inst->min_samples = min_samples;
+  inst->max_samples = max_samples;
+
   SST_SetRefid(inst, refid, addr);
   SST_ResetInstance(inst);
 
@@ -262,7 +263,7 @@ SST_AccumulateSample(SST_Stats inst, struct timeval *sample_time,
 
   /* Make room for the new sample */
   if (inst->n_samples > 0 &&
-      (inst->n_samples == MAX_SAMPLES || inst->n_samples == max_samples)) {
+      (inst->n_samples == MAX_SAMPLES || inst->n_samples == inst->max_samples)) {
     prune_register(inst, 1);
   }
 
@@ -447,7 +448,7 @@ SST_DoNewRegression(SST_Stats inst)
   inst->regression_ok = RGR_FindBestRegression(times_back + inst->runs_samples,
                                          offsets + inst->runs_samples, weights,
                                          inst->n_samples, inst->runs_samples,
-                                         min_samples,
+                                         inst->min_samples,
                                          &est_intercept, &est_slope, &est_var,
                                          &est_intercept_sd, &est_slope_sd,
                                          &best_start, &nruns, &degrees_of_freedom);

sourcestats.h

@@ -38,7 +38,7 @@ extern void SST_Initialise(void);
 extern void SST_Finalise(void);
 
 /* This function creates a new instance of the statistics handler */
-extern SST_Stats SST_CreateInstance(uint32_t refid, IPAddr *addr);
+extern SST_Stats SST_CreateInstance(uint32_t refid, IPAddr *addr, int min_samples, int max_samples);
 
 /* This function deletes an instance of the statistics handler. */
 extern void SST_DeleteInstance(SST_Stats inst);

srcparams.h

@@ -40,6 +40,8 @@ typedef struct {
   int poll_target;
   int version;
   int max_sources;
+  int min_samples;
+  int max_samples;
   uint32_t authkey;
   double max_delay;
   double max_delay_ratio;
@@ -57,6 +59,8 @@ typedef struct {
 #define SRC_DEFAULT_MINSTRATUM 0
 #define SRC_DEFAULT_POLLTARGET 6
 #define SRC_DEFAULT_MAXSOURCES 4
+#define SRC_DEFAULT_MINSAMPLES (-1)
+#define SRC_DEFAULT_MAXSAMPLES (-1)
 #define INACTIVE_AUTHKEY 0
 
 #endif /* GOT_SRCPARAMS_H */