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sources: include maxclockerror in source selection

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In the source selection algorithm, include extra dispersion due to
maxclockerror in the root distance of sources that don't have new
samples (the last sample is older than span of all samples) to not
prefer unreachable sources with a short distance and small skew over
reachable sources for too long, and also to decrease their chances of
becoming falsetickers.
This commit is contained in:
Miroslav Lichvar 2018-02-22 17:30:23 +01:00
parent da862158bf
commit 5308e0a25f
1 changed files with 10 additions and 0 deletions
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10
sources.c
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@ -665,6 +665,16 @@ SRC_SelectSource(SRC_Instance updated_inst)
continue;
}
/* Include extra dispersion in the root distance of sources that don't
have new samples (the last sample is older than span of all samples) */
if (first_sample_ago < 2.0 * si->last_sample_ago) {
double extra_disp = LCL_GetMaxClockError() *
(2.0 * si->last_sample_ago - first_sample_ago);
si->root_distance += extra_disp;
si->lo_limit -= extra_disp;
si->hi_limit += extra_disp;
}
/* Require the root distance to be below the allowed maximum */
if (si->root_distance > max_distance) {
sources[i]->status = SRC_BAD_DISTANCE;