Improve the svm fifo allocator

- Round up requested fifo size to the next power of two
- Maintain per-segment power-of-two freelists
- Allocate fifos in chunks, to amortize alignment overhead
- Detach builtin test client application after each run
  so we can use different fifo sizes each time
- Be more suspicious of session / application indices

Useful prep work for dynamically resizing fifos. As far as the svm
fifo code is concerned, it's OK to set fifo->nitems anywhere in the
interval: [0, 1<<(fifo->freelist_index) + FIFO_SEGMENT_MIN_FIFO_SIZE]

It's unlikely that setting nitems below the path MTU will work out
very well...

Change-Id: Idad73a027dfb7412056cb02988b77e300fa7e8a7
Signed-off-by: Dave Barach <dave@barachs.net>

2 files changed, 24 insertions, 3 deletions

diff --git a/src/vnet/session/session.c b/src/vnet/session/session.c
index 991bcd5a53f..533a6c22ae0 100644
--- a/src/vnet/session/session.c
+++ b/src/vnet/session/session.c
@@ -266,7 +266,13 @@ stream_session_enqueue_notify (stream_session_t * s, u8 block)
     return 0;
 
   /* Get session's server */
-  app = application_get (s->app_index);
+  app = application_get_if_valid (s->app_index);
+
+  if (PREDICT_FALSE (app == 0))
+    {
+      clib_warning ("invalid s->app_index = %d", s->app_index);
+      return 0;
+    }
 
   /* Built-in server? Hand event to the callback... */
   if (app->cb_fns.builtin_server_rx_callback)
@@ -327,8 +333,9 @@ session_manager_flush_enqueue_events (u32 thread_index)
       stream_session_t *s0;
 
       /* Get session */
-      s0 = stream_session_get (session_indices_to_enqueue[i], thread_index);
-      if (stream_session_enqueue_notify (s0, 0 /* don't block */ ))
+      s0 = stream_session_get_if_valid (session_indices_to_enqueue[i],
+					thread_index);
+      if (s0 == 0 || stream_session_enqueue_notify (s0, 0 /* don't block */ ))
 	{
 	  errors++;
 	}
diff --git a/src/vnet/tcp/builtin_client.c b/src/vnet/tcp/builtin_client.c
index 938e07ba505..5fa5446091c 100644
--- a/src/vnet/tcp/builtin_client.c
+++ b/src/vnet/tcp/builtin_client.c
@@ -713,6 +713,20 @@ cleanup:
 
   pool_free (tm->sessions);
 
+  /* Detach the application, so we can use different fifo sizes next time */
+  if (tm->test_client_attached)
+    {
+      vnet_app_detach_args_t _da, *da = &_da;
+      int rv;
+
+      da->app_index = tm->app_index;
+
+      rv = vnet_application_detach (da);
+      if (rv)
+	vlib_cli_output (vm, "WARNING: app detach failed...");
+      tm->test_client_attached = 0;
+      tm->app_index = ~0;
+    }
   return 0;
 }