RedisConnection#Connect(): get rid of spin lock

Instead of IoEngine::YieldCurrentCoroutine(yc) until m_Queues.FutureResponseActions.empty(), async-wait a CV which is updated along with m_Queues.FutureResponseActions.
Icinga · Jan 29, 2025 · fd24514 · fd24514
1 parent 364cc6e
commit fd24514
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Showing 2 changed files with 5 additions and 10 deletions.
diff --git a/lib/icingadb/redisconnection.cpp b/lib/icingadb/redisconnection.cpp
@@ -302,12 +302,6 @@ void RedisConnection::Connect(asio::yield_context& yc)
 
 	boost::asio::deadline_timer timer (m_Strand.context());
 
-	auto waitForReadLoop ([this, &yc]() {
-		while (!m_Queues.FutureResponseActions.empty()) {
-			IoEngine::YieldCurrentCoroutine(yc);
-		}
-	});
-
 	for (;;) {
 		try {
 			if (m_Path.IsEmpty()) {
@@ -339,7 +333,7 @@ void RedisConnection::Connect(asio::yield_context& yc)
 					}
 
 					Handshake(conn, yc);
-					waitForReadLoop();
+					m_QueuedReads.Wait(yc, false);
 					m_TlsConn = std::move(conn);
 				} else {
 					Log(m_Parent ? LogNotice : LogInformation, "IcingaDB")
@@ -350,7 +344,7 @@ void RedisConnection::Connect(asio::yield_context& yc)
 
 					icinga::Connect(conn->next_layer(), m_Host, Convert::ToString(m_Port), yc);
 					Handshake(conn, yc);
-					waitForReadLoop();
+					m_QueuedReads.Wait(yc, false);
 					m_TcpConn = std::move(conn);
 				}
 			} else {
@@ -362,7 +356,7 @@ void RedisConnection::Connect(asio::yield_context& yc)
 
 				conn->next_layer().async_connect(Unix::endpoint(m_Path.CStr()), yc);
 				Handshake(conn, yc);
-				waitForReadLoop();
+				m_QueuedReads.Wait(yc, false);
 				m_UnixConn = std::move(conn);
 			}
 

diff --git a/lib/icingadb/redisconnection.hpp b/lib/icingadb/redisconnection.hpp
@@ -262,7 +262,8 @@ namespace icinga
 		std::set<QueryPriority> m_SuppressedQueryKinds;
 
 		// Indicate that there's something to send/receive
-		AsioEvent m_QueuedWrites, m_QueuedReads;
+		AsioEvent m_QueuedWrites;
+		AsioSymmetricEvent m_QueuedReads;
 
 		std::function<void(boost::asio::yield_context& yc)> m_ConnectedCallback;