diff options
author | Philipp Maier <pmaier@sysmocom.de> | 2021-06-14 17:54:38 +0200 |
---|---|---|
committer | Philipp Maier <pmaier@sysmocom.de> | 2021-07-06 11:35:50 +0200 |
commit | dda5cf4bb7622eba600042464910c02fab1aaa49 (patch) | |
tree | 5c5fc2e2f635fe967831f155b44fb22d4ed37132 | |
parent | a5602d593ce14077152b921e53bb37b66e1c579c (diff) |
paging: prioritize CS related paging over PS related pagings.
When the paging queue is filled up to a critical level, pagings from the
PCU should be dropped as each immediate assignment paging from the PCU
is worth 4 normal CS pagings. Also the PCU may still issue pagings if the
paginging queue is already full and CS pagings are dropped. In a
congestion situation it is more important to get the CS rather than PS
pagings through.
Change-Id: I30f97672d7a0c369c4a656e878ab8cbbd83e31ea
Related: SYS#5306
-rw-r--r-- | include/osmo-bts/bts.h | 2 | ||||
-rw-r--r-- | include/osmo-bts/paging.h | 2 | ||||
-rw-r--r-- | src/common/bts.c | 2 | ||||
-rw-r--r-- | src/common/paging.c | 47 | ||||
-rw-r--r-- | src/common/pcu_sock.c | 2 |
5 files changed, 52 insertions, 3 deletions
diff --git a/include/osmo-bts/bts.h b/include/osmo-bts/bts.h index e1166182..6a61d015 100644 --- a/include/osmo-bts/bts.h +++ b/include/osmo-bts/bts.h @@ -18,7 +18,9 @@ enum bts_global_status { enum { BTS_CTR_PAGING_RCVD, BTS_CTR_PAGING_DROP, + BTS_CTR_PAGING_DROP_PS, BTS_CTR_PAGING_SENT, + BTS_CTR_PAGING_CONG, BTS_CTR_RACH_RCVD, BTS_CTR_RACH_DROP, BTS_CTR_RACH_HO, diff --git a/include/osmo-bts/paging.h b/include/osmo-bts/paging.h index 7fc0bf05..ef1fc93d 100644 --- a/include/osmo-bts/paging.h +++ b/include/osmo-bts/paging.h @@ -37,7 +37,7 @@ int paging_add_identity(struct paging_state *ps, uint8_t paging_group, /* Add an IMM.ASS message to the paging queue */ int paging_add_imm_ass(struct paging_state *ps, const uint8_t *data, - uint8_t len); + uint8_t len, bool from_pcu); /* generate paging message for given gsm time */ int paging_gen_msg(struct paging_state *ps, uint8_t *out_buf, struct gsm_time *gt, diff --git a/src/common/bts.c b/src/common/bts.c index d2226997..27c7f74c 100644 --- a/src/common/bts.c +++ b/src/common/bts.c @@ -90,6 +90,8 @@ static int bts_signal_cbfn(unsigned int subsys, unsigned int signal, static const struct rate_ctr_desc bts_ctr_desc[] = { [BTS_CTR_PAGING_RCVD] = {"paging:rcvd", "Received paging requests (Abis)"}, [BTS_CTR_PAGING_DROP] = {"paging:drop", "Dropped paging requests (Abis)"}, + [BTS_CTR_PAGING_DROP_PS] = {"paging:drop-ps", "Dropped paging requests (PS/PCU)"}, + [BTS_CTR_PAGING_CONG] = {"paging:cong", "Paging congestion detected (Abis)"}, [BTS_CTR_PAGING_SENT] = {"paging:sent", "Sent paging requests (Um)"}, [BTS_CTR_RACH_RCVD] = {"rach:rcvd", "Received RACH requests (Um)"}, diff --git a/src/common/paging.c b/src/common/paging.c index 29731419..54d72635 100644 --- a/src/common/paging.c +++ b/src/common/paging.c @@ -80,8 +80,37 @@ struct paging_state { /* total number of currently active paging records in queue */ unsigned int num_paging; struct llist_head paging_queue[MAX_PAGING_BLOCKS_CCCH*MAX_BS_PA_MFRMS]; + + /* prioritization of cs pagings will automatically become + * active on congestions (queue almost full) */ + bool cs_priority_active; }; +/* The prioritization of cs pagings is controlled by a hysteresis. When the + * fill state of the paging queue exceeds the upper fill level + * THRESHOLD_CONGESTED [%], then PS pagings (immediate assignments) will be + * dropped until fill state of the paging queue drops under the lower fill + * level THRESHOLD_CLEAR [%]. */ +#define THRESHOLD_CONGESTED 66 /* (percent of num_paging_max) */ +#define THRESHOLD_CLEAR 50 /* (percent of num_paging_max) */ + +/* Check the queue fill status and decide if prioritization of CS pagings + * must be turned on to flatten the negative effects of the congestion + * situation on the CS domain. */ +static void check_congestion(struct paging_state *ps) +{ + int pag_queue_len = paging_queue_length(ps); + int pag_queue_max = paging_get_queue_max(ps); + unsigned int treshold_upper = pag_queue_max * THRESHOLD_CONGESTED / 100; + unsigned int treshold_lower = pag_queue_max * THRESHOLD_CLEAR / 100; + + if (pag_queue_len > treshold_upper && ps->cs_priority_active == false) { + ps->cs_priority_active = true; + rate_ctr_inc2(ps->bts->ctrs, BTS_CTR_PAGING_CONG); + } else if (pag_queue_len < treshold_lower) + ps->cs_priority_active = false; +} + unsigned int paging_get_lifetime(struct paging_state *ps) { return ps->paging_lifetime; @@ -181,6 +210,8 @@ int paging_add_identity(struct paging_state *ps, uint8_t paging_group, int blocks = gsm48_number_of_paging_subchannels(&ps->chan_desc); struct paging_record *pr; + check_congestion(ps); + rate_ctr_inc2(ps->bts->ctrs, BTS_CTR_PAGING_RCVD); if (paging_group >= blocks) { @@ -238,12 +269,21 @@ int paging_add_identity(struct paging_state *ps, uint8_t paging_group, /* Add an IMM.ASS message to the paging queue */ int paging_add_imm_ass(struct paging_state *ps, const uint8_t *data, - uint8_t len) + uint8_t len, bool from_pcu) { struct llist_head *group_q; struct paging_record *pr; uint16_t imsi, paging_group; + check_congestion(ps); + + if (ps->cs_priority_active && from_pcu) { + LOGP(DPAG, LOGL_NOTICE, "Dropping paging for PS, queue congested (%u)\n", + ps->num_paging); + rate_ctr_inc2(ps->bts->ctrs, BTS_CTR_PAGING_DROP_PS); + return -ENOSPC; + } + if (len != GSM_MACBLOCK_LEN + 3) { LOGP(DPAG, LOGL_ERROR, "IMM.ASS invalid length %d\n", len); return -EINVAL; @@ -530,6 +570,10 @@ int paging_gen_msg(struct paging_state *ps, uint8_t *out_buf, struct gsm_time *g int group; int len; + /* This will have no effect on behavior of this function, we just need + * need to check the congestion status of the queue from time to time. */ + check_congestion(ps); + *is_empty = 0; bts->load.ccch.pch_total += 1; @@ -711,6 +755,7 @@ struct paging_state *paging_init(struct gsm_bts *bts, ps->bts = bts; ps->paging_lifetime = paging_lifetime; ps->num_paging_max = num_paging_max; + ps->cs_priority_active = false; for (i = 0; i < ARRAY_SIZE(ps->paging_queue); i++) INIT_LLIST_HEAD(&ps->paging_queue[i]); diff --git a/src/common/pcu_sock.c b/src/common/pcu_sock.c index 41a5ffc5..03f1a05d 100644 --- a/src/common/pcu_sock.c +++ b/src/common/pcu_sock.c @@ -673,7 +673,7 @@ static int pcu_rx_data_req(struct gsm_bts *bts, uint8_t msg_type, switch (data_req->sapi) { case PCU_IF_SAPI_PCH: - paging_add_imm_ass(bts->paging_state, data_req->data, data_req->len); + paging_add_imm_ass(bts->paging_state, data_req->data, data_req->len, true); break; case PCU_IF_SAPI_AGCH: msg = msgb_alloc(data_req->len, "pcu_agch"); |