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authorOliver Smith <osmith@sysmocom.de>2021-08-19 11:58:09 +0200
committerosmith <osmith@sysmocom.de>2021-08-20 14:04:54 +0000
commit11da4a4abde8fa3db07492e7f6695667fe4c4be9 (patch)
treefa2b4886ed0fc338aa7517b33f9dd7c21737c5b8
parenta79a549273de9fbd014f2602ebe1885d308e531e (diff)
stats: send real last value if no new values come
Background: * Individual values can be added to osmo_stat_item.values at any time. * Stats are reported at a fixed interval (see vty 'stats interval'), e.g. every 10 seconds. * In order to report a new stat value, we use the maximum of all osmo_stat_item.values added since the last report. * By default, we do not send new stat values if they did not change (see vty 'config-stats' -> 'flush-period' default of 0). Fix the following bug: * If 'flush-period' is 0, and no new osmo_stat_item.values are coming in, the last value that gets reported is not necessarily the last entry in osmo_stat_item.values. * For attached reporters (statsd), it could then be that the given stat stays at the wrong value for a long stretch of time (think of several hours/days/forever). Explanation of how the test shows that it is fixed: * stats get reported (value is irrelevant) * osmo_stat_item gets a new value: 20 * osmo_stat_item gets a new value: 10 * stats get reported (value: 20, the maximum of both new values) * osmo_stat_item gets no new values * stats get reported (value: 10, this is new because of the bug fix, the real last value in osmo_stat_item, different from the 20 sent earlier, without the fix it would not send anything here and the last sent value would be 20) * osmo_stat_item gets no new values * stats get reported (nothing gets sent, since the real last value was already sent and 'flush-period' is 0) Fixes: OS#5215 Change-Id: Ibeefd0e3d1dbe4be454ff05a21df4848b2abfabe
-rw-r--r--TODO-RELEASE1
-rw-r--r--include/osmocom/core/stat_item.h4
-rw-r--r--src/stats.c7
-rw-r--r--tests/stats/stats_test.c2
-rw-r--r--tests/stats/stats_test.err2
5 files changed, 15 insertions, 1 deletions
diff --git a/TODO-RELEASE b/TODO-RELEASE
index 260e1d4a..c8966cd3 100644
--- a/TODO-RELEASE
+++ b/TODO-RELEASE
@@ -15,3 +15,4 @@ libosmovty vty_read_config_filep New API
libosmosim osim_card_{reset,close} New API
libosmocore struct rate_ctr_group, osmo_stat_item_group_desc ABI breakage due to new struct members
libosmgsm kdf functions New API
+libosmocore osmo_stat_item ABI + API breakage due to new struct members
diff --git a/include/osmocom/core/stat_item.h b/include/osmocom/core/stat_item.h
index fbe04332..332bbe92 100644
--- a/include/osmocom/core/stat_item.h
+++ b/include/osmocom/core/stat_item.h
@@ -28,6 +28,10 @@ struct osmo_stat_item {
* be read from the FIFO. If accessing osmo_stat_item directly, without
* the stats API, store this value elsewhere. */
int32_t stats_next_id;
+ /* internal use by stats API: indicate if the last value sent to
+ * reporters was actually the last value in the FIFO. This may not be
+ * the case, as always a max of 1 or more values gets sent (OS#5215) */
+ bool stats_last_sent_was_max;
/*! the index of the last value written to the FIFO */
int16_t last_offs;
/*! value FIFO */
diff --git a/src/stats.c b/src/stats.c
index 411ecff9..f06515dd 100644
--- a/src/stats.c
+++ b/src/stats.c
@@ -715,6 +715,11 @@ static int osmo_stat_item_handler(
if (!have_value) {
/* Send the last value in case a flush is requested */
value = osmo_stat_item_get_last(item);
+
+ /* Also send it in case a different max value was sent
+ * previously (OS#5215) */
+ if (!item->stats_last_sent_was_max)
+ have_value = 1;
} else {
int32_t next_val;
/* If we have multiple values only send the max */
@@ -722,6 +727,8 @@ static int osmo_stat_item_handler(
value = OSMO_MAX(value, next_val);
}
+ item->stats_last_sent_was_max = (osmo_stat_item_get_last(item) == value);
+
llist_for_each_entry(srep, &osmo_stats_reporter_list, list) {
if (!srep->running)
continue;
diff --git a/tests/stats/stats_test.c b/tests/stats/stats_test.c
index 6505e669..2f2c6ecc 100644
--- a/tests/stats/stats_test.c
+++ b/tests/stats/stats_test.c
@@ -445,7 +445,7 @@ static void test_reporting()
fprintf(stderr, "report (group 1, item 1 no update, send last item (!= last max), OS#5215):\n");
send_count = 0;
osmo_stats_report();
- OSMO_ASSERT(send_count == 0); /* BUG: should be 2! */
+ OSMO_ASSERT(send_count == 2);
fprintf(stderr, "report (group 1, item 1 no update, nothing to send):\n");
send_count = 0;
diff --git a/tests/stats/stats_test.err b/tests/stats/stats_test.err
index 08c2cbcd..daa3e5ce 100644
--- a/tests/stats/stats_test.err
+++ b/tests/stats/stats_test.err
@@ -116,6 +116,8 @@ report (group 1, item 1 update twice, check max):
test2: item p= g=test.one i=1 n=item.a v=20 u=ma
test1: item p= g=test.one i=1 n=item.a v=20 u=ma
report (group 1, item 1 no update, send last item (!= last max), OS#5215):
+ test2: item p= g=test.one i=1 n=item.a v=10 u=ma
+ test1: item p= g=test.one i=1 n=item.a v=10 u=ma
report (group 1, item 1 no update, nothing to send):
report (remove statg1, ctrg1):
test2: counter p= g=ctr-test:one_dot i=3 n=ctr:a v=0 d=0