Change in osmo-bsc[master]: paging: Fix recalculate work timer if waiting for retrans

pespin has uploaded this change for review. ( https://gerrit.osmocom.org/c/osmo-bsc/+/28052 ) Change subject: paging: Fix recalculate work timer if waiting for retrans ...................................................................... paging: Fix recalculate work timer if waiting for retrans We want to recalculate the timer based on last time the work_timer was triggered (that is, the time when the worker re-armed the pag req to retransmit). We don't want to recalculate based on the last time the pag ret tro retransmit was scheduled. In loaded paging queue, there's lots of retrans (let's say 200) and it may take more than 500ms to actually retransmit them. That means in most cases we could end up in a situation where only pag req to retrans where in the queue, hitting this recalculate path. Since the 500ms were for sure elapsed, that would most probably schedule the work_timer at {0,0} for each new paging request that arrived. As a result, the worker would be scheduled lots of times per second (once for each new req arriving) and only submitting 1 pag req (the new one) plus potentially 1 or serveral pag req to retransmit. In summary, there was not throthling applied in the scenario where only pag req to retransmit where in the queue and new pag reqs kept arriving. This incurrs into augmented paging throughput and also augmented frequency of polls(). Related: OS#5922 Fixes: 4821c9f4dff3cb9d06ee8392de18fd7c63399bf0 Change-Id: I7ce6f436286b50dc31331d218ff256cf7be3f619 --- M include/osmocom/bsc/paging.h M src/osmo-bsc/paging.c 2 files changed, 5 insertions(+), 4 deletions(-) git pull ssh://gerrit.osmocom.org:29418/osmo-bsc refs/changes/52/28052/1 diff --git a/include/osmocom/bsc/paging.h b/include/osmocom/bsc/paging.h index 9b63225..9eddda0 100644 --- a/include/osmocom/bsc/paging.h +++ b/include/osmocom/bsc/paging.h @@ -106,6 +106,9 @@ struct osmo_timer_list work_timer; struct osmo_timer_list credit_timer; + /* Last time paging worker was triggered */ + struct timespec last_sched_ts; + /* free chans needed */ int free_chans_need; diff --git a/src/osmo-bsc/paging.c b/src/osmo-bsc/paging.c index 2246918..6e888d4 100644 --- a/src/osmo-bsc/paging.c +++ b/src/osmo-bsc/paging.c @@ -225,6 +225,7 @@ goto sched_next_iter; osmo_clock_gettime(CLOCK_MONOTONIC, &now); + paging_bts->last_sched_ts = now; /* do while loop: Try send at most first MAX_PAGE_REQ_PER_ITER paging * requests (or before if there are no more available slots). Since @@ -458,11 +459,8 @@ * which is a longer period. * Let's recaculate the time to adapt it to initial_period: */ struct timespec now, elapsed, tdiff; - struct gsm_paging_request *first_retrans_req; osmo_clock_gettime(CLOCK_MONOTONIC, &now); - /* This is what used to be the first req (retrans state) in the queue: */ - first_retrans_req = llist_entry(req->entry.next, struct gsm_paging_request, entry); - timespecsub(&now, &first_retrans_req->last_attempt_ts, &elapsed); + timespecsub(&now, &bts_entry->last_sched_ts, &elapsed); if (timespeccmp(&elapsed, &initial_period, <)) { timespecsub(&initial_period, &elapsed, &tdiff); } else { -- To view, visit https://gerrit.osmocom.org/c/osmo-bsc/+/28052 To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings Gerrit-Project: osmo-bsc Gerrit-Branch: master Gerrit-Change-Id: I7ce6f436286b50dc31331d218ff256cf7be3f619 Gerrit-Change-Number: 28052 Gerrit-PatchSet: 1 Gerrit-Owner: pespin &lt;pespin(a)sysmocom.de&gt; Gerrit-MessageType: newchange