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sources: update reference only with new sample

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This follows the section 11.2.3. from RFC 5905.
This commit is contained in:
Miroslav Lichvar 2014-10-16 15:28:12 +02:00
parent 819b8eb73d
commit e930d94728
2 changed files with 17 additions and 12 deletions
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21
sources.c
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@ -100,6 +100,9 @@ struct SRC_Instance_Record {
/* Number of set bits in the reachability register */
int reachability_size;
/* Updates since last reference update */
int updates;
/* Updates left before allowing combining */
int outlier;
@ -226,6 +229,7 @@ SRC_Instance SRC_CreateNewInstance(uint32_t ref_id, SRC_Type type, SRC_SelectOpt
result->ip_addr = addr;
result->active = 0;
result->selectable = 0;
result->updates = 0;
result->reachability = 0;
result->reachability_size = 0;
result->outlier = 0;
@ -562,10 +566,7 @@ combine_sources(int n_sel_sources, struct timeval *ref_time, double *offset,
/* ================================================== */
/* This function selects the current reference from amongst the pool
of sources we are holding.
Updates are only made to the local reference if a new source is selected
or match_refid is equal to the selected reference source refid */
of sources we are holding and updates the local reference */
void
SRC_SelectSource(SRC_Instance updated_inst)
@ -589,6 +590,9 @@ SRC_SelectSource(SRC_Instance updated_inst)
NTP_Leap leap_status = LEAP_Normal;
old_selected_index = selected_source_index;
if (updated_inst)
updated_inst->updates++;
if (n_sources == 0) {
/* In this case, we clearly cannot synchronise to anything */
if (selected_source_index != INVALID_SOURCE) {
@ -940,10 +944,8 @@ SRC_SelectSource(SRC_Instance updated_inst)
sources[selected_source_index]->status = SRC_SYNC;
/* Update local reference only when a new source was selected
or the selected source has a new sample */
if (selected_source_index != old_selected_index ||
updated_inst == sources[selected_source_index]) {
/* Update reference only when the selected source has a new sample */
if (sources[selected_source_index]->updates) {
/* Now just use the statistics of the selected source combined with
the other selectable sources for trimming the local clock */
@ -968,6 +970,9 @@ SRC_SelectSource(SRC_Instance updated_inst)
src_skew,
src_root_delay,
src_root_dispersion);
for (i = 0; i < n_sources; i++)
sources[i]->updates = 0;
}
} else {

8
sources.h
View file

@ -140,11 +140,11 @@ extern void SRC_ResetReachability(SRC_Instance inst);
/* This routine is used to select the best source from amongst those
we currently have valid data on, and use it as the tracking base
for the local time. Updates are only made to the local reference
if a new source is selected or updated_inst is the selected
reference source. (This avoids updating the frequency
for the local time. Updates are made to the local reference only
when the selected source was updated (set as updated_inst) since
the last reference update. This avoids updating the frequency
tracking for every sample from other sources - only the ones from
the selected reference make a difference) */
the selected reference make a difference. */
extern void SRC_SelectSource(SRC_Instance updated_inst);
/* Force reselecting the best source */