From: Willy Tarreau <w@1wt.eu>
Date: Sat, 27 May 2023 18:35:15 +0000 (+0000)
Subject: MINOR: stick-table: move the task_wakeup() call outside of the lock
X-Git-Tag: v2.9-dev3~25
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=73b1dea4d104d38e22cc898cf12499a778bd754e;p=thirdparty%2Fhaproxy.git

MINOR: stick-table: move the task_wakeup() call outside of the lock

The write lock in stktable_touch_with_exp() is quite expensive and should
be shortened as much as possible. There's no need for it when calling
task_wakeup() so let's move it out.

On a 80-thread machine with a peers section, the request rate increased
from 397k to 415k rps.
---

diff --git a/src/stick_table.c b/src/stick_table.c
index ba6e3c4308..ae6b79f605 100644
--- a/src/stick_table.c
+++ b/src/stick_table.c
@@ -424,6 +424,7 @@ void stktable_touch_with_exp(struct stktable *t, struct stksess *ts, int local,
 {
 	struct eb32_node * eb;
 	int locked = 0;
+	int do_wakeup = 0;
 
 	if (expire != HA_ATOMIC_LOAD(&ts->expire)) {
 		/* we'll need to set the expiration and to wake up the expiration timer .*/
@@ -452,7 +453,7 @@ void stktable_touch_with_exp(struct stktable *t, struct stksess *ts, int local,
 					eb32_insert(&t->updates, &ts->upd);
 				}
 			}
-			task_wakeup(t->sync_task, TASK_WOKEN_MSG);
+			do_wakeup = 1;
 		}
 		else {
 			/* If this entry is not in the tree */
@@ -482,6 +483,9 @@ void stktable_touch_with_exp(struct stktable *t, struct stksess *ts, int local,
 
 	if (locked)
 		HA_RWLOCK_WRUNLOCK(STK_TABLE_LOCK, &t->lock);
+
+	if (do_wakeup)
+		task_wakeup(t->sync_task, TASK_WOKEN_MSG);
 }
 
 /* Update the expiration timer for <ts> but do not touch its expiration node.