session: measure dispatch period only if under load

[vpp.git] / src / vnet / session / session_node.c

diff --git a/src/vnet/session/session_node.c b/src/vnet/session/session_node.c
index 04a5622..5ed681d 100644 (file)
--- a/src/vnet/session/session_node.c
+++ b/src/vnet/session/session_node.c
@@ -570,7 +570,8 @@ session_tx_fifo_read_and_snd_i (vlib_main_t * vm, vlib_node_runtime_t * node,
   ctx->tc = session_tx_get_transport (ctx, peek_data);
   ctx->snd_mss = ctx->transport_vft->send_mss (ctx->tc);
   ctx->snd_space =
-    transport_connection_max_tx_burst (ctx->tc, vm->clib_time.last_cpu_time);
+    transport_connection_snd_space (ctx->tc, vm->clib_time.last_cpu_time,
+                                   ctx->snd_mss);
   if (ctx->snd_space == 0 || ctx->snd_mss == 0)
     {
       vec_add1 (wrk->pending_event_vector, *e);
@@ -750,10 +751,12 @@ static void
 session_update_dispatch_period (session_manager_worker_t * wrk, f64 now,
                                u32 thread_index)
 {
-  f64 sample, prev_period = wrk->dispatch_period, a = 0.8;
-
-  sample = now - wrk->last_vlib_time;
-  wrk->dispatch_period = a * sample + (1 - a) * prev_period;
+  if (wrk->last_tx_packets > 8)
+    {
+      f64 sample = now - wrk->last_vlib_time;
+      sample = (sample * wrk->last_tx_packets) / VLIB_FRAME_SIZE;
+      wrk->dispatch_period = (wrk->dispatch_period + sample) * 0.5;
+    }
   wrk->last_vlib_time = now;
 }
 
@@ -764,8 +767,7 @@ session_queue_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
   session_manager_main_t *smm = vnet_get_session_manager_main ();
   u32 thread_index = vm->thread_index, n_to_dequeue, n_events;
   session_manager_worker_t *wrk = &smm->wrk[thread_index];
-  session_event_t *pending_events, *e;
-  session_event_t *fifo_events;
+  session_event_t *e, *fifo_events;
   svm_msg_q_msg_t _msg, *msg = &_msg;
   f64 now = vlib_time_now (vm);
   int n_tx_packets = 0, i, rv;
@@ -782,55 +784,39 @@ session_queue_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
   session_update_dispatch_period (wrk, now, thread_index);
   transport_update_time (now, thread_index);
 
-  /*
-   * Get vpp queue events that we can dequeue without blocking
-   */
-  mq = wrk->vpp_event_queue;
-  fifo_events = wrk->free_event_vector;
-  n_to_dequeue = svm_msg_q_size (mq);
-  pending_events = wrk->pending_event_vector;
-
-  if (!n_to_dequeue && !vec_len (pending_events)
-      && !vec_len (wrk->pending_disconnects))
-    return 0;
-
   SESSION_EVT_DBG (SESSION_EVT_DEQ_NODE, 0);
 
-  /*
-   * If we didn't manage to process previous events try going
-   * over them again without dequeuing new ones.
-   * XXX: Handle senders to sessions that can't keep up
-   */
-  if (0 && vec_len (pending_events) >= 100)
-    {
-      clib_warning ("too many fifo events unsolved");
-      goto skip_dequeue;
-    }
+  /* Make sure postponed events are handled first */
+  fifo_events = wrk->free_event_vector;
+  vec_append (fifo_events, wrk->postponed_event_vector);
+  _vec_len (wrk->pending_disconnects) = 0;
 
-  /* See you in the next life, don't be late
+  /* Try to dequeue what is available. Don't wait for lock.
    * XXX: we may need priorities here */
-  if (svm_msg_q_try_lock (mq))
-    return 0;
-
-  for (i = 0; i < n_to_dequeue; i++)
+  mq = wrk->vpp_event_queue;
+  n_to_dequeue = svm_msg_q_size (mq);
+  if (n_to_dequeue && svm_msg_q_try_lock (mq) == 0)
     {
-      vec_add2 (fifo_events, e, 1);
-      svm_msg_q_sub_w_lock (mq, msg);
-      clib_memcpy (e, svm_msg_q_msg_data (mq, msg), sizeof (*e));
-      svm_msg_q_free_msg (mq, msg);
+      for (i = 0; i < n_to_dequeue; i++)
+       {
+         vec_add2 (fifo_events, e, 1);
+         svm_msg_q_sub_w_lock (mq, msg);
+         clib_memcpy (e, svm_msg_q_msg_data (mq, msg), sizeof (*e));
+         svm_msg_q_free_msg (mq, msg);
+       }
+      svm_msg_q_unlock (mq);
     }
 
-  svm_msg_q_unlock (mq);
-
-  vec_append (fifo_events, pending_events);
+  vec_append (fifo_events, wrk->pending_event_vector);
   vec_append (fifo_events, wrk->pending_disconnects);
 
-  _vec_len (pending_events) = 0;
-  wrk->pending_event_vector = pending_events;
-  _vec_len (wrk->pending_disconnects) = 0;
+  _vec_len (wrk->postponed_event_vector) = 0;
+  _vec_len (wrk->pending_event_vector) = 0;
 
-skip_dequeue:
   n_events = vec_len (fifo_events);
+  if (PREDICT_FALSE (!n_events))
+    return 0;
+
   for (i = 0; i < n_events; i++)
     {
       stream_session_t *s;     /* $$$ prefetch 1 ahead maybe */
@@ -844,7 +830,7 @@ skip_dequeue:
          /* Don't try to send more that one frame per dispatch cycle */
          if (n_tx_packets == VLIB_FRAME_SIZE)
            {
-             vec_add1 (wrk->pending_event_vector, *e);
+             vec_add1 (wrk->postponed_event_vector, *e);
              break;
            }
 
@@ -933,6 +919,7 @@ skip_dequeue:
 
   _vec_len (fifo_events) = 0;
   wrk->free_event_vector = fifo_events;
+  wrk->last_tx_packets = n_tx_packets;
 
   vlib_node_increment_counter (vm, session_queue_node.index,
                               SESSION_QUEUE_ERROR_TX, n_tx_packets);