jetty-9: HTTP client: avoid double dispatch for SSL, and made I/O dispatch a configurable parameter.

jetty-client/src/main/java/org/eclipse/jetty/client/HttpClient.java

@@ -122,6 +122,7 @@ public class HttpClient extends ContainerLifeCycle
     private volatile SocketAddress bindAddress;
     private volatile long idleTimeout;
     private volatile boolean tcpNoDelay = true;
+    private volatile boolean dispatchIO = true;
 
     public HttpClient()
     {
@@ -142,7 +143,11 @@ public class HttpClient extends ContainerLifeCycle
     protected void doStart() throws Exception
     {
         if (sslContextFactory != null)
+        {
             addBean(sslContextFactory);
+            // Avoid to double dispatch when using SSL
+            setDispatchIO(false);
+        }
 
         if (executor == null)
             executor = new QueuedThreadPool();
@@ -524,6 +529,32 @@ public class HttpClient extends ContainerLifeCycle
         this.tcpNoDelay = tcpNoDelay;
     }
 
+    /**
+     * @return true to dispatch I/O operations in a different thread, false to execute them in the selector thread
+     * @see #setDispatchIO(boolean)
+     */
+    public boolean isDispatchIO()
+    {
+        return dispatchIO;
+    }
+
+    /**
+     * Whether to dispatch I/O operations from the selector thread to a different thread.
+     * <p />
+     * This implementation never blocks on I/O operation, but invokes application callbacks that may
+     * take time to execute or block on other I/O.
+     * If application callbacks are known to take time or block on I/O, then parameter {@code dispatchIO}
+     * must be set to true.
+     * If application callbacks are known to be quick and never block on I/O, then parameter {@code dispatchIO}
+     * may be set to false.
+     *
+     * @param dispatchIO true to dispatch I/O operations in a different thread, false to execute them in the selector thread
+     */
+    public void setDispatchIO(boolean dispatchIO)
+    {
+        this.dispatchIO = dispatchIO;
+    }
+
     @Override
     public void dump(Appendable out, String indent) throws IOException
     {

jetty-client/src/main/java/org/eclipse/jetty/client/HttpConnection.java

@@ -58,7 +58,7 @@ public class HttpConnection extends AbstractConnection implements Connection
 
     public HttpConnection(HttpClient client, EndPoint endPoint, HttpDestination destination)
     {
-        super(endPoint, client.getExecutor());
+        super(endPoint, client.getExecutor(), client.isDispatchIO());
         this.client = client;
         this.destination = destination;
         this.sender = new HttpSender(this);

jetty-client/src/main/java/org/eclipse/jetty/client/HttpDestination.java

@@ -174,7 +174,7 @@ public class HttpDestination implements Destination, AutoCloseable, Dumpable
                     public void completed(Connection connection)
                     {
                         LOG.debug("Created connection {}/{} {} for {}", next, maxConnections, connection, HttpDestination.this);
-                        process(connection, true);
+                        process(connection, client.isDispatchIO());
                     }
 
                     @Override

jetty-client/src/test/java/org/eclipse/jetty/client/HttpClientLoadTest.java

@@ -65,6 +65,7 @@ public class HttpClientLoadTest extends AbstractHttpClientServerTest
 
         client.setMaxConnectionsPerAddress(32768);
         client.setMaxQueueSizePerAddress(1024 * 1024);
+        client.setDispatchIO(false);
 
         Random random = new Random();
         int iterations = 200;