Add TCP_NODELAY to disable Nagle's algorithm in Boost.ASIO-based http_client (microsoft#1310)

* Add TCP_NODELAY to disable Nagle's algorithm to avoid waiting for ACK for HTTP request headers before transmitting the request body, in order to significantly improve performance for requests with bodies (see microsoft#1201)

* Also add TCP_NODELAY on the server-side, to disable Nagle's algorithm to avoid waiting for ACK for HTTP response headers before transmitting the response body (see microsoft#1201)

Author: garethsb

Release/src/http/client/http_client_asio.cpp

@@ -330,6 +330,12 @@ class asio_connection
 
     void start_reuse() { m_is_reused = true; }
 
+    void enable_no_delay()
+    {
+        boost::asio::ip::tcp::no_delay option(true);
+        m_socket.set_option(option);
+    }
+
 private:
     // Guards concurrent access to socket/ssl::stream. This is necessary
     // because timeouts and cancellation can touch the socket at the same time
@@ -610,6 +616,7 @@ class asio_context final : public request_context, public std::enable_shared_fro
             if (!ec)
             {
                 m_context->m_timer.reset();
+                m_context->m_connection->enable_no_delay();
                 m_context->m_connection->async_write(m_request,
                                                      boost::bind(&ssl_proxy_tunnel::handle_write_request,
                                                                  shared_from_this(),
@@ -1006,6 +1013,7 @@ class asio_context final : public request_context, public std::enable_shared_fro
         m_timer.reset();
         if (!ec)
         {
+            m_connection->enable_no_delay();
             write_request();
         }
         else if (ec.value() == boost::system::errc::operation_canceled ||

Release/src/http/listener/http_server_asio.cpp

@@ -593,6 +593,9 @@ void hostport_listener::on_accept(std::unique_ptr<ip::tcp::socket> socket, const
     // Handle successful accept
     if (!ec)
     {
+        boost::asio::ip::tcp::no_delay option(true);
+        socket->set_option(option);
+
         auto conn = asio_server_connection::create(std::move(socket), m_p_server, this);
 
         m_connections.insert(conn.get());