pespin has submitted this change. (
https://gerrit.osmocom.org/c/osmo-bsc/+/31811 )
Change subject: bscc_sccp: Small optimiztion in bsc_sccp_inst_next_conn_id()
......................................................................
bscc_sccp: Small optimiztion in bsc_sccp_inst_next_conn_id()
Refactor the double loop to check a code path matching the sccp_instance
once instead of doing so for every subscr_conn.
If for instance let's say we have 1000 concurrent calls in progress,
which means we have 1000 subscr_conn, which means we at least do the
extra check regarding SMLC vs MSC 1000 times (at least, xN times if N
conn_id already used are already found).
That overhead happens every time a new subscr_conn is created (which in
a BSC with already 1000 concurrent calls can potentially happen quite
frequently).
Change-Id: Ic32b1eeb201fc51110e1ee130110824845f81e82
---
M src/osmo-bsc/bsc_sccp.c
1 file changed, 51 insertions(+), 13 deletions(-)
Approvals:
fixeria: Looks good to me, but someone else must approve
Jenkins Builder: Verified
laforge: Looks good to me, approved
diff --git a/src/osmo-bsc/bsc_sccp.c b/src/osmo-bsc/bsc_sccp.c
index 431e194..e0cce39 100644
--- a/src/osmo-bsc/bsc_sccp.c
+++ b/src/osmo-bsc/bsc_sccp.c
@@ -47,6 +47,33 @@
/* This looks really suboptimal, but in most cases the static next_id
should indicate exactly the next unused
* conn_id, and we only iterate all conns once to make super sure that
it is not already in use. */
+ /* SCCP towards SMLC: */
+ if (bsc_gsmnet->smlc->sccp == sccp) {
+ for (i = 0; i < SCCP_CONN_ID_MAX; i++) {
+ struct gsm_subscriber_connection *conn;
+ uint32_t conn_id = next_id;
+ bool conn_id_already_used = false;
+
+ /* Optimized modulo operation (% SCCP_CONN_ID_MAX)
using bitwise AND plus CMP: */
+ next_id = (next_id + 1) & 0x00FFFFFF;
+ if (OSMO_UNLIKELY(next_id == 0x00FFFFFF))
+ next_id = 0;
+
+ llist_for_each_entry(conn, &bsc_gsmnet->subscr_conns,
entry) {
+ if (conn->lcs.lb.state != SUBSCR_SCCP_ST_NONE &&
+ conn->lcs.lb.conn_id == conn_id) {
+ conn_id_already_used = true;
+ break;
+ }
+ }
+
+ if (!conn_id_already_used)
+ return conn_id;
+ }
+ return 0xFFFFFFFF;
+ }
+
+ /* SCCP towards MSC: */
for (i = 0; i < SCCP_CONN_ID_MAX; i++) {
struct gsm_subscriber_connection *conn;
uint32_t conn_id = next_id;
@@ -58,19 +85,10 @@
next_id = 0;
llist_for_each_entry(conn, &bsc_gsmnet->subscr_conns, entry) {
- if (conn->sccp.msc && conn->sccp.msc->a.sccp == sccp) {
- if (conn_id == conn->sccp.conn_id) {
- conn_id_already_used = true;
- break;
- }
- }
-
- if (bsc_gsmnet->smlc->sccp == sccp
- && conn->lcs.lb.state != SUBSCR_SCCP_ST_NONE) {
- if (conn_id == conn->lcs.lb.conn_id) {
- conn_id_already_used = true;
- break;
- }
+ if (conn->sccp.msc && conn->sccp.msc->a.sccp == sccp &&
+ conn->sccp.conn_id == conn_id) {
+ conn_id_already_used = true;
+ break;
}
}
--
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Gerrit-Project: osmo-bsc
Gerrit-Branch: master
Gerrit-Change-Id: Ic32b1eeb201fc51110e1ee130110824845f81e82
Gerrit-Change-Number: 31811
Gerrit-PatchSet: 3
Gerrit-Owner: pespin <[email protected]>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: fixeria <[email protected]>
Gerrit-Reviewer: laforge <[email protected]>
Gerrit-Reviewer: neels <[email protected]>
Gerrit-Reviewer: pespin <[email protected]>
Gerrit-MessageType: merged
