msg/DispatchQueue: wake up only one dispatch thread

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 <max.kellermann@ionos.com>

diff --git a/src/msg/DispatchQueue.cc b/src/msg/DispatchQueue.cc
index b8ed6f7efe8f6ca1d6a4427834a0f6e4407f85fc..4694bdff587135cc2406f97b411392a8bcb92b7d 100644 (file)
--- 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)