session: async rx event notifications

Move from synchronous flushing of io and ctrl events from transports to
applications to an async model via a new session_input input node that
runs in interrupt mode. Events are coalesced per application worker.

On the one hand, this helps by minimizing message queue locking churn.
And on the other, it opens the possibility for further optimizations of
event message generation, obviates need for rx rescheduling rpcs and is
a first step towards a fully async data/io rx path.

Type: improvement

Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: Id6bebcb65fc9feef8aa02ddf1af6d9ba6f6745ce

1 files changed, 50 insertions, 0 deletions

diff --git a/src/vnet/session/session_api.c b/src/vnet/session/session_api.c
index ff11bcb690a..55fc72ee4c2 100644
--- a/src/vnet/session/session_api.c
+++ b/src/vnet/session/session_api.c
@@ -460,6 +460,52 @@ mq_send_session_cleanup_cb (session_t * s, session_cleanup_ntf_t ntf)
   app_wrk_send_ctrl_evt (app_wrk, SESSION_CTRL_EVT_CLEANUP, &m, sizeof (m));
 }
 
+static int
+mq_send_io_rx_event (session_t *s)
+{
+  session_event_t *mq_evt;
+  svm_msg_q_msg_t mq_msg;
+  app_worker_t *app_wrk;
+  svm_msg_q_t *mq;
+
+  if (svm_fifo_has_event (s->rx_fifo))
+    return 0;
+
+  app_wrk = app_worker_get (s->app_wrk_index);
+  mq = app_wrk->event_queue;
+
+  mq_msg = svm_msg_q_alloc_msg_w_ring (mq, SESSION_MQ_IO_EVT_RING);
+  mq_evt = svm_msg_q_msg_data (mq, &mq_msg);
+
+  mq_evt->event_type = SESSION_IO_EVT_RX;
+  mq_evt->session_index = s->rx_fifo->shr->client_session_index;
+
+  (void) svm_fifo_set_event (s->rx_fifo);
+
+  svm_msg_q_add_raw (mq, &mq_msg);
+
+  return 0;
+}
+
+static int
+mq_send_io_tx_event (session_t *s)
+{
+  app_worker_t *app_wrk = app_worker_get (s->app_wrk_index);
+  svm_msg_q_t *mq = app_wrk->event_queue;
+  session_event_t *mq_evt;
+  svm_msg_q_msg_t mq_msg;
+
+  mq_msg = svm_msg_q_alloc_msg_w_ring (mq, SESSION_MQ_IO_EVT_RING);
+  mq_evt = svm_msg_q_msg_data (mq, &mq_msg);
+
+  mq_evt->event_type = SESSION_IO_EVT_TX;
+  mq_evt->session_index = s->tx_fifo->shr->client_session_index;
+
+  svm_msg_q_add_raw (mq, &mq_msg);
+
+  return 0;
+}
+
 static session_cb_vft_t session_mq_cb_vft = {
   .session_accept_callback = mq_send_session_accepted_cb,
   .session_disconnect_callback = mq_send_session_disconnected_cb,
@@ -469,6 +515,8 @@ static session_cb_vft_t session_mq_cb_vft = {
   .session_cleanup_callback = mq_send_session_cleanup_cb,
   .add_segment_callback = mq_send_add_segment_cb,
   .del_segment_callback = mq_send_del_segment_cb,
+  .builtin_app_rx_callback = mq_send_io_rx_event,
+  .builtin_app_tx_callback = mq_send_io_tx_event,
 };
 
 static void
@@ -1246,6 +1294,8 @@ static session_cb_vft_t session_mq_sapi_cb_vft = {
   .session_cleanup_callback = mq_send_session_cleanup_cb,
   .add_segment_callback = mq_send_add_segment_sapi_cb,
   .del_segment_callback = mq_send_del_segment_sapi_cb,
+  .builtin_app_rx_callback = mq_send_io_rx_event,
+  .builtin_app_tx_callback = mq_send_io_tx_event,
 };
 
 static void