stat_item: make value ids item specific

Fix counting of values missed because of FIFO overflow in
osmo_stat_item_get_next(), by assigning a new item value id effectively
as item->value[n + 1].id = item->value[n].id + 1, instead of increasing
a global_value_id that is shared between all items and groups. With
global_value_id, the count of values missed was wrong for one item, as
soon as a new value was added to another item.

This partially reverts b27b352e ("stats: Use a global index for stat
item values") from 2015, right after stats was added to libosmocore. It
was supposed to make multiple readers (reporters) possible, which could
read independently from stat_item (and later added comments explain it
like that). But this remained unused, stats has implemented multiple
reporters by reading all stat_items once and sending the same data to
all enabled reporters. The patch caused last_value_index in struct
osmo_stat_item to always remain at -1.

Replace this unused last_value_index with stats_next_id, so stats can
store the item-specific next_id in the struct again. It appears that
stats is the only direct user of osmo_stat_item, but if there are
others, they can bring their own item-specific next_id: functions in
stat_item.c still accept a next_id argument.

Related: OS#5088
Change-Id: Ie65dcdf52c8fc3d916e20d7f0455f6223be6b64f

1 files changed, 0 insertions, 15 deletions

diff --git a/tests/stats/stats_test.c b/tests/stats/stats_test.c
index e5f7f20f..b6b4be9d 100644
--- a/tests/stats/stats_test.c
+++ b/tests/stats/stats_test.c
@@ -234,21 +234,6 @@ static void stat_test(void)
 	rc = osmo_stat_item_get_next(statg->items[TEST_A_ITEM], &next_id_a, &value);
 	OSMO_ASSERT(rc == 0);
 
-	/* Test Discard (all items) */
-	osmo_stat_item_set(statg->items[TEST_A_ITEM], 99);
-	osmo_stat_item_set(statg->items[TEST_A_ITEM], 100);
-	osmo_stat_item_set(statg->items[TEST_A_ITEM], 101);
-	osmo_stat_item_set(statg->items[TEST_B_ITEM], 99);
-	osmo_stat_item_set(statg->items[TEST_B_ITEM], 100);
-
-	rc = osmo_stat_item_discard_all(&next_id_a);
-	rc = osmo_stat_item_discard_all(&next_id_b);
-
-	rc = osmo_stat_item_get_next(statg->items[TEST_A_ITEM], &next_id_a, &value);
-	OSMO_ASSERT(rc == 0);
-	rc = osmo_stat_item_get_next(statg->items[TEST_B_ITEM], &next_id_b, &value);
-	OSMO_ASSERT(rc == 0);
-
 	osmo_stat_item_group_free(statg);
 
 	sgrp2 = osmo_stat_item_get_group_by_name_idx("test.one", 0);