MEDIUM: stream-int: make si_connect() return an established state when possible

si_connect() used to only return SI_ST_CON. But it already detect the
connection reuse and is the function which avoids calling connect().
So it already knows the connection is valid and reuse. Thus we make it
return SI_ST_EST when a connection is reused. This means that
connect_server() can return this state and sess_update_stream_int()
as well.

Thanks to this change, we don't need to leave process_session() in
SI_ST_CON state to immediately enter it again to switch to SI_ST_EST.
Implementing this removes one call to process_session() per request
in keep-alive mode. We're now at 2 calls per request, which is the
minimum (one for the request and another one for the response). The
number of calls to http_wait_for_response() has also dropped from 2
to one.

Tests indicate a performance gain of about 2.6% in request rate in
keep-alive mode. There should be no gain in http-server-close() since
we don't use this faster path.

diff --git a/include/proto/stream_interface.h b/include/proto/stream_interface.h
index 6d4da780680082b31e2e7a18cf2e01b4f189b89b..418fc8392cc3fa90e50e055ae0fab1c4dcc56dcd 100644 (file)
--- a/include/proto/stream_interface.h
+++ b/include/proto/stream_interface.h
@@ -323,24 +323,27 @@ static inline int si_connect(struct stream_interface *si)
                ret = conn->ctrl->connect(conn, !channel_is_empty(si->ob), 0);
                if (ret != SN_ERR_NONE)
                        return ret;
+
+               /* we need to be notified about connection establishment */
+               conn->flags |= CO_FL_WAKE_DATA;
+
+               /* we're in the process of establishing a connection */
+               si->state = SI_ST_CON;
        }
        else if (!channel_is_empty(si->ob)) {
                /* reuse the existing connection, we'll have to send a
                 * request there.
                 */
                conn_data_want_send(conn);
+
+               /* the connection is established */
+               si->state = SI_ST_EST;
        }
 
        /* needs src ip/port for logging */
        if (si->flags & SI_FL_SRC_ADDR)
                conn_get_from_addr(conn);
 
-       /* we need to be notified about connection establishment */
-       conn->flags |= CO_FL_WAKE_DATA;
-
-       /* we're in the process of establishing a connection */
-       si->state = SI_ST_CON;
-
        return ret;
 }
 

diff --git a/src/session.c b/src/session.c
index de78e7e27e7b43c1bc3da5cd30b854699ecc5558..b2486334d93c635d900f56c72f0fd02d144e7b16 100644 (file)
--- a/src/session.c
+++ b/src/session.c
@@ -957,8 +957,9 @@ static void sess_establish(struct session *s, struct stream_interface *si)
 
 /* Update stream interface status for input states SI_ST_ASS, SI_ST_QUE, SI_ST_TAR.
  * Other input states are simply ignored.
- * Possible output states are SI_ST_CLO, SI_ST_TAR, SI_ST_ASS, SI_ST_REQ, SI_ST_CON.
- * Flags must have previously been updated for timeouts and other conditions.
+ * Possible output states are SI_ST_CLO, SI_ST_TAR, SI_ST_ASS, SI_ST_REQ, SI_ST_CON
+ * and SI_ST_EST. Flags must have previously been updated for timeouts and other
+ * conditions.
  */
 static void sess_update_stream_int(struct session *s, struct stream_interface *si)
 {
@@ -980,7 +981,7 @@ static void sess_update_stream_int(struct session *s, struct stream_interface *s
                srv = objt_server(s->target);
 
                if (conn_err == SN_ERR_NONE) {
-                       /* state = SI_ST_CON now */
+                       /* state = SI_ST_CON or SI_ST_EST now */
                        if (srv)
                                srv_inc_sess_ctr(srv);
                        return;
@@ -2225,7 +2226,10 @@ struct task *process_session(struct task *t)
                        if (s->si[1].state == SI_ST_REQ)
                                sess_prepare_conn_req(s, &s->si[1]);
 
-                       /* applets directly go to the ESTABLISHED state */
+                       /* applets directly go to the ESTABLISHED state. Similarly,
+                        * servers experience the same fate when their connection
+                        * is reused.
+                        */
                        if (unlikely(s->si[1].state == SI_ST_EST))
                                sess_establish(s, &s->si[1]);