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authorDaniel Baumann <daniel.baumann@progress-linux.org>2019-11-28 04:53:08 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2019-11-28 04:53:08 +0000
commit315e0143f65da3485dcbcd2f6a3172a351618aec (patch)
treeb713ae472cffab249c95917c6fb6d242d54e0a87 /database/rrdset.c
parentAdding upstream version 1.18.1. (diff)
downloadnetdata-315e0143f65da3485dcbcd2f6a3172a351618aec.tar.xz
netdata-315e0143f65da3485dcbcd2f6a3172a351618aec.zip
Adding upstream version 1.19.0.upstream/1.19.0
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r--database/rrdset.c38
1 files changed, 26 insertions, 12 deletions
diff --git a/database/rrdset.c b/database/rrdset.c
index e96d707be..0f5297030 100644
--- a/database/rrdset.c
+++ b/database/rrdset.c
@@ -1447,9 +1447,11 @@ void rrdset_done(RRDSET *st) {
continue;
}
- // if the new is smaller than the old (an overflow, or reset), set the old equal to the new
- // to reset the calculation (it will give zero as the calculation for this second)
- if(unlikely(rd->last_collected_value > rd->collected_value)) {
+ // If the new is smaller than the old (an overflow, or reset), set the old equal to the new
+ // to reset the calculation (it will give zero as the calculation for this second).
+ // It is imperative to set the comparison to uint64_t since type collected_number is signed and
+ // produces wrong results as far as incremental counters are concerned.
+ if(unlikely((uint64_t)rd->last_collected_value > (uint64_t)rd->collected_value)) {
debug(D_RRD_STATS, "%s.%s: RESET or OVERFLOW. Last collected value = " COLLECTED_NUMBER_FORMAT ", current = " COLLECTED_NUMBER_FORMAT
, st->name, rd->name
, rd->last_collected_value
@@ -1463,17 +1465,29 @@ void rrdset_done(RRDSET *st) {
uint64_t max = (uint64_t)rd->collected_value_max;
uint64_t cap = 0;
- if(max > 0x00000000FFFFFFFFULL) cap = 0xFFFFFFFFFFFFFFFFULL;
- else if(max > 0x000000000000FFFFULL) cap = 0x00000000FFFFFFFFULL;
- else if(max > 0x00000000000000FFULL) cap = 0x000000000000FFFFULL;
- else cap = 0x00000000000000FFULL;
+ // Signed values are handled by exploiting two's complement which will produce positive deltas
+ if (max > 0x00000000FFFFFFFFULL)
+ cap = 0xFFFFFFFFFFFFFFFFULL; // handles signed and unsigned 64-bit counters
+ else
+ cap = 0x00000000FFFFFFFFULL; // handles signed and unsigned 32-bit counters
uint64_t delta = cap - last + new;
-
- rd->calculated_value +=
- (calculated_number) delta
- * (calculated_number) rd->multiplier
- / (calculated_number) rd->divisor;
+ uint64_t max_acceptable_rate = (cap / 100) * MAX_INCREMENTAL_PERCENT_RATE;
+
+ // If the delta is less than the maximum acceptable rate and the previous value was near the cap
+ // then this is an overflow. There can be false positives such that a reset is detected as an
+ // overflow.
+ // TODO: remember recent history of rates and compare with current rate to reduce this chance.
+ if (delta < max_acceptable_rate) {
+ rd->calculated_value +=
+ (calculated_number) delta
+ * (calculated_number) rd->multiplier
+ / (calculated_number) rd->divisor;
+ } else {
+ // This is a reset. Any overflow with a rate greater than MAX_INCREMENTAL_PERCENT_RATE will also
+ // be detected as a reset instead.
+ rd->calculated_value += (calculated_number)0;
+ }
}
else {
rd->calculated_value +=