Add stat items for the BTS's channel load average and T3122.

In addition to logging the current values of a BTS's channel load
average and T3122 override, maintain stat items for these values.
This allows for plotting these values over time, for instance.

These values show up in the VTY under 'show stats' like this:

base transceiver station:
 Channel load average.:       25 %
 T3122 IMMEDIATE ASSIGNMENT REJECT wait indicator.: 32 s

Port of osmo-bsc commit 4e9d40db2f86bfbd4d9c8bf9e3d9196f5ddf22c6

Change-Id: I766bd51f539dd96236b9c81d661e9d31f5027db4

4 files changed, 28 insertions, 1 deletions

diff --git a/openbsc/include/openbsc/gsm_data.h b/openbsc/include/openbsc/gsm_data.h
index b12c4edc3..b823acc65 100644
--- a/openbsc/include/openbsc/gsm_data.h
+++ b/openbsc/include/openbsc/gsm_data.h
@@ -10,6 +10,7 @@
 #include <osmocom/core/rate_ctr.h>
 #include <osmocom/core/select.h>
 #include <osmocom/core/stats.h>
+#include <osmocom/core/stat_item.h>
 
 #include <osmocom/crypt/auth.h>
 
@@ -175,6 +176,10 @@ struct gsm_subscriber_connection {
 #define ROLE_BSC
 #include "gsm_data_shared.h"
 
+enum {
+	BTS_STAT_CHAN_LOAD_AVERAGE,
+	BTS_STAT_T3122,
+};
 
 enum {
 	BSC_CTR_CHREQ_TOTAL,
diff --git a/openbsc/include/openbsc/gsm_data_shared.h b/openbsc/include/openbsc/gsm_data_shared.h
index a78e2eb7a..47c5faef4 100644
--- a/openbsc/include/openbsc/gsm_data_shared.h
+++ b/openbsc/include/openbsc/gsm_data_shared.h
@@ -907,6 +907,8 @@ struct gsm_bts {
 	char *pcu_sock_path;
 	struct pcu_sock_state *pcu_state;
 
+	struct osmo_stat_item_group *bts_statg;
+
 	/* BTS-specific overrides for timer values from struct gsm_network. */
 	uint8_t T3122;	/* ASSIGMENT REJECT wait indication */
 
diff --git a/openbsc/src/libbsc/chan_alloc.c b/openbsc/src/libbsc/chan_alloc.c
index 2fd197f60..b27ac8fd2 100644
--- a/openbsc/src/libbsc/chan_alloc.c
+++ b/openbsc/src/libbsc/chan_alloc.c
@@ -609,6 +609,8 @@ bts_update_t3122_chan_load(struct gsm_bts *bts)
 	load = ((used / total) * 100);
 	LOGP(DRLL, LOGL_DEBUG, "(bts=%d) channel load average is %lu.%.2lu%%\n",
 	     bts->nr, (load & 0xffffff00) >> 8, (load & 0xff) / 10);
+	osmo_stat_item_set(bts->bts_statg->items[BTS_STAT_CHAN_LOAD_AVERAGE],
+			   (load & 0xffffff00) >> 8);
 
 	/* Calculate new T3122 wait indicator. */
 	wait_ind = ((used / total) * max_wait_ind);
@@ -620,4 +622,5 @@ bts_update_t3122_chan_load(struct gsm_bts *bts)
 
 	LOGP(DRLL, LOGL_DEBUG, "(bts=%d) T3122 wait indicator set to %lu seconds\n", bts->nr, wait_ind);
 	bts->T3122 = (uint8_t)wait_ind;
+	osmo_stat_item_set(bts->bts_statg->items[BTS_STAT_T3122], wait_ind);
 }
diff --git a/openbsc/src/libcommon/gsm_data_shared.c b/openbsc/src/libcommon/gsm_data_shared.c
index a1d7a50b4..37baec341 100644
--- a/openbsc/src/libcommon/gsm_data_shared.c
+++ b/openbsc/src/libcommon/gsm_data_shared.c
@@ -30,10 +30,24 @@
 #include <osmocom/core/talloc.h>
 #include <osmocom/gsm/gsm_utils.h>
 #include <osmocom/gsm/abis_nm.h>
-#include <osmocom/core/statistics.h>
+#include <osmocom/core/counter.h>
+#include <osmocom/core/stats.h>
 
 #include <openbsc/gsm_data.h>
 
+static const struct osmo_stat_item_desc bts_stat_desc[] = {
+	{ "chanloadavg", "Channel load average.", "%", 16, 0 },
+	{ "T3122", "T3122 IMMEDIATE ASSIGNMENT REJECT wait indicator.", "s", 16, GSM_T3122_DEFAULT },
+};
+
+static const struct osmo_stat_item_group_desc bts_statg_desc = {
+	.group_name_prefix = "bts",
+	.group_description = "base transceiver station",
+	.class_id = OSMO_STATS_CLASS_GLOBAL,
+	.num_items = ARRAY_SIZE(bts_stat_desc),
+	.item_desc = bts_stat_desc,
+};
+
 void gsm_abis_mo_reset(struct gsm_abis_mo *mo)
 {
 	mo->nm_state.operational = NM_OPSTATE_NULL;
@@ -347,9 +361,12 @@ struct gsm_bts *gsm_bts_alloc(void *ctx, uint8_t bts_num)
 	memcpy(&bts->gprs.cell.rlc_cfg, &rlc_cfg_default,
 		sizeof(bts->gprs.cell.rlc_cfg));
 
+	bts->bts_statg = osmo_stat_item_group_alloc(bts, &bts_statg_desc, 0);
+
 	/* create our primary TRX */
 	bts->c0 = gsm_bts_trx_alloc(bts);
 	if (!bts->c0) {
+		osmo_stat_item_group_free(bts->bts_statg);
 		talloc_free(bts);
 		return NULL;
 	}