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authorPau Espin Pedrol <pespin@sysmocom.de>2022-11-29 12:37:53 +0100
committerPau Espin Pedrol <pespin@sysmocom.de>2022-11-30 20:23:39 +0100
commit867e73e96b1cea41ba09cbb9c3c41db91e9e4d65 (patch)
treef97c8f62dc98f61aceaffe50a2b9274c7e778987
parentd681b897b60f5ff91ac339edb3e449877a649ae8 (diff)
paging: Optimize retrieving number of request per paging group
This patch caches the counts of initial paging requests for each paging group. This count is needed to estimate T3113 when a new incoming paging request is received and it has to be inserted into the queue. With this there's no need to traverse the whole initial_req_list every time a new incoming paging request is receiving, potentially saving lots of iteration and hence lots of CPU when the queue is long. Related: SYS#6200 Change-Id: I6994127827d120a0b4dd3de51e1ddde39f2fe531
-rw-r--r--include/osmocom/bsc/paging.h6
-rw-r--r--src/osmo-bsc/paging.c31
2 files changed, 17 insertions, 20 deletions
diff --git a/include/osmocom/bsc/paging.h b/include/osmocom/bsc/paging.h
index b10c39893..15eb49e43 100644
--- a/include/osmocom/bsc/paging.h
+++ b/include/osmocom/bsc/paging.h
@@ -61,6 +61,9 @@ enum bsc_paging_reason {
*/
#define PAGING_THRESHOLD_X3113_DEFAULT_SEC 60
+#define MAX_PAGING_BLOCKS_CCCH 9
+#define MAX_BS_PA_MFRMS 9
+
struct bsc_paging_params {
enum bsc_paging_reason reason;
struct bsc_msc_data *msc;
@@ -117,6 +120,9 @@ struct gsm_bts_paging_state {
/* Number of requests in pending_requests_len */
unsigned int retrans_req_list_len;
+ /* Number of requests in initial_req_list, indexed by pgroup. */
+ unsigned int initial_req_pgroup_counts[MAX_PAGING_BLOCKS_CCCH * MAX_BS_PA_MFRMS];
+
struct gsm_bts *bts;
struct osmo_timer_list work_timer;
diff --git a/src/osmo-bsc/paging.c b/src/osmo-bsc/paging.c
index 657665c14..e6f6fe4ef 100644
--- a/src/osmo-bsc/paging.c
+++ b/src/osmo-bsc/paging.c
@@ -88,10 +88,12 @@ static void paging_remove_request(struct gsm_paging_request *req)
osmo_timer_del(&req->T3113);
llist_del(&req->entry);
- if (req->attempts == 0)
+ if (req->attempts == 0) {
bts_pag_st->initial_req_list_len--;
- else
+ bts_pag_st->initial_req_pgroup_counts[req->pgroup]--;
+ } else {
bts_pag_st->retrans_req_list_len--;
+ }
osmo_stat_item_dec(osmo_stat_item_group_get_item(bts->bts_statg, BTS_STAT_PAGING_REQ_QUEUE_LENGTH), 1);
bsc_subscr_remove_active_paging_request(req->bsub, req);
talloc_free(req);
@@ -220,6 +222,7 @@ static void paging_req_timeout_retrans(struct gsm_paging_request *request, const
if (request->attempts == 0) {
/* req is removed from initial_req_list and inserted into retrans_req_list, update list lengths: */
bts_pag_st->initial_req_list_len--;
+ bts_pag_st->initial_req_pgroup_counts[request->pgroup]--;
bts_pag_st->retrans_req_list_len++;
}
llist_del(&request->entry);
@@ -503,9 +506,8 @@ static int _paging_request(const struct bsc_paging_params *params, struct gsm_bt
struct gsm_paging_request *req;
unsigned int t3113_timeout_s;
unsigned int x3113_s = osmo_tdef_get(bts->network->T_defs, -3113, OSMO_TDEF_S, -1);
- unsigned int reqs_before = 0, reqs_before_same_pgroup = 0;
- uint8_t pgroup = gsm0502_calc_paging_group(&bts->si_common.chan_desc,
- str_to_imsi(params->bsub->imsi));
+ uint8_t pgroup;
+ unsigned int reqs_before, reqs_before_same_pgroup;
rate_ctr_inc(rate_ctr_group_get_ctr(bts->bts_ctrs, BTS_CTR_PAGING_ATTEMPTED));
@@ -530,21 +532,9 @@ static int _paging_request(const struct bsc_paging_params *params, struct gsm_bt
paging_remove_request(first_retrans_req);
}
- /* The incoming new req will be stored in initial_req_list giving higher prio
- * to it over retransmissions. This avoids new subscribers being paged to
- * be delayed if the paging queue is full due to a lot of retranmissions.
- * Retranmissions usually mean MS are not reachable/available, so the
- * rationale here is to prioritize new subs which may be available.
- *
- * Count initial reqs already stored in initial_req_list, since those
- * will be scheduled for transmission before current incoming req and
- need to be taken into account when calculating T3113 for it.
- */
- llist_for_each_entry(req, &bts_entry->initial_req_list, entry) {
- reqs_before++;
- if (req->pgroup == pgroup)
- reqs_before_same_pgroup++;
- }
+ pgroup = gsm0502_calc_paging_group(&bts->si_common.chan_desc, str_to_imsi(params->bsub->imsi));
+ reqs_before = bts_entry->initial_req_list_len;
+ reqs_before_same_pgroup = bts_entry->initial_req_pgroup_counts[pgroup];
LOG_PAGING_BTS(params, bts, DPAG, LOGL_DEBUG, "Start paging\n");
req = talloc_zero(tall_paging_ctx, struct gsm_paging_request);
@@ -559,6 +549,7 @@ static int _paging_request(const struct bsc_paging_params *params, struct gsm_bt
bsc_subscr_add_active_paging_request(req->bsub, req);
bts_entry->initial_req_list_len++;
+ bts_entry->initial_req_pgroup_counts[req->pgroup]++;
osmo_stat_item_inc(osmo_stat_item_group_get_item(bts->bts_statg, BTS_STAT_PAGING_REQ_QUEUE_LENGTH), 1);
llist_add_tail(&req->entry, &bts_entry->initial_req_list);