msg/DispatchQueue: wake up only one dispatch thread

MaxKellermann · MaxKellermann · commit 23fd2cc44864 · 2024-10-07T22:50:20.000+02:00
When adding one message, only one thread needs to be woken up.  Waking
up all is a more expensive operation and leads to unnecessary lock
contention and context switches.

Signed-off-by: Max Kellermann &lt;max.kellermann@ionos.com&gt;
diff --git a/src/msg/DispatchQueue.cc b/src/msg/DispatchQueue.cc
@@ -93,7 +93,7 @@ void DispatchQueue::enqueue(const ref_t<Message>& m, int priority, uint64_t id)
   } else {
     mqueue.enqueue(id, priority, m->get_cost(), QueueItem(m));
   }
-  cond.notify_all();
+  cond.notify_one();
 }
 
 void DispatchQueue::local_delivery(const ref_t<Message>& m, int priority)

Original file line number	Diff line number	Diff line change
`@@ -93,7 +93,7 @@ void DispatchQueue::enqueue(const ref_t<Message>& m, int priority, uint64_t id)`
`93`	`93`	`} else {`
`94`	`94`	`mqueue.enqueue(id, priority, m->get_cost(), QueueItem(m));`
`95`	`95`	`}`
`96`		`- cond.notify_all();`
	`96`	`+ cond.notify_one();`
`97`	`97`	`}`
`98`	`98`
`99`	`99`	`void DispatchQueue::local_delivery(const ref_t<Message>& m, int priority)`