From: Olivier Houchard <ohouchard@haproxy.com>
Date: Wed, 1 Apr 2026 13:08:26 +0000 (+0200)
Subject: MINOR: servers: Don't update last_sess if it did not change
X-Git-Tag: v3.4-dev8~69
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=e264523112b94ceacf34428d1bdd4e8eea4a813d;p=thirdparty%2Fhaproxy.git

MINOR: servers: Don't update last_sess if it did not change

Check that last_sess actually changed before attempting to set it, as it
should only change once every second, that will avoid a lot of atomic
writes on a busy cache line.
---

diff --git a/include/haproxy/server.h b/include/haproxy/server.h
index 6294bf246..6bdd823f2 100644
--- a/include/haproxy/server.h
+++ b/include/haproxy/server.h
@@ -220,8 +220,12 @@ static inline void srv_inc_sess_ctr(struct server *s)
 /* set the time of last session on the designated server */
 static inline void srv_set_sess_last(struct server *s)
 {
-	if (s->counters.shared.tg)
-		HA_ATOMIC_STORE(&s->counters.shared.tg[tgid - 1]->last_sess,  ns_to_sec(now_ns));
+	if (s->counters.shared.tg) {
+		uint now_sec = ns_to_sec(now_ms);
+
+		if (HA_ATOMIC_LOAD(&s->counters.shared.tg[tgid - 1]->last_sess) != now_sec)
+			HA_ATOMIC_STORE(&s->counters.shared.tg[tgid - 1]->last_sess, now_sec);
+	}
 }
 
 /* returns the current server throttle rate between 0 and 100% */