session/svm: add want_tx_event flag to fifo

Have applications use explicit flag to request events from vpp when it
transmits from a full fifo.

Change-Id: I687c8f050a066bd5ce739d880eaec1f286038d95
Signed-off-by: Florin Coras <fcoras@cisco.com>

6 files changed, 42 insertions, 36 deletions

diff --git a/src/svm/svm_fifo.h b/src/svm/svm_fifo.h
index ec32fd5f40d..1ac5b6363cd 100644
--- a/src/svm/svm_fifo.h
+++ b/src/svm/svm_fifo.h
@@ -62,6 +62,7 @@ typedef struct _svm_fifo
   u32 segment_manager;
     CLIB_CACHE_LINE_ALIGN_MARK (end_shared);
   u32 head;
+  volatile u32 want_tx_evt;	/**< producer wants nudge */
     CLIB_CACHE_LINE_ALIGN_MARK (end_consumer);
 
   /* producer */
@@ -169,6 +170,18 @@ svm_fifo_unset_event (svm_fifo_t * f)
   __sync_lock_release (&f->has_event);
 }
 
+static inline void
+svm_fifo_set_want_tx_evt (svm_fifo_t * f, u8 want_evt)
+{
+  f->want_tx_evt = want_evt;
+}
+
+static inline u8
+svm_fifo_want_tx_evt (svm_fifo_t * f)
+{
+  return f->want_tx_evt;
+}
+
 svm_fifo_t *svm_fifo_create (u32 data_size_in_bytes);
 void svm_fifo_free (svm_fifo_t * f);
 
diff --git a/src/vcl/sock_test_server.c b/src/vcl/sock_test_server.c
index 1280429f0f6..896aeb024d8 100644
--- a/src/vcl/sock_test_server.c
+++ b/src/vcl/sock_test_server.c
@@ -24,6 +24,7 @@
 #include <vcl/sock_test.h>
 #include <sys/stat.h>
 #include <fcntl.h>
+#include <sys/ioctl.h>
 
 #define SOCK_SERVER_USE_EPOLL 1
 #define VPPCOM_SESSION_ATTR_UNIT_TEST 0
@@ -828,6 +829,7 @@ main (int argc, char **argv)
 	  if (EPOLLIN & ssm->wait_events[i].events)
 #endif
 	    {
+	    read_again:
 	      rx_bytes = sock_test_read (client_fd, conn->buf,
 					 conn->buf_size, &conn->stats);
 	      if (rx_bytes > 0)
@@ -910,6 +912,8 @@ main (int argc, char **argv)
 			   (conn->cfg.test == SOCK_TEST_TYPE_BI))
 		    {
 		      stream_test_server (conn, rx_bytes);
+		      if (ioctl (conn->fd, FIONREAD))
+			goto read_again;
 		      continue;
 		    }
 
diff --git a/src/vcl/vcl_debug.h b/src/vcl/vcl_debug.h
index 52a3d94b63f..7b284166503 100644
--- a/src/vcl/vcl_debug.h
+++ b/src/vcl/vcl_debug.h
@@ -19,9 +19,10 @@
 #include <vppinfra/elog.h>
 
 #define VCL_ELOG	0
+#define VCL_DBG_ON	1
 
 #define VDBG(_lvl, _fmt, _args...) 					\
-  if (vcm->debug > _lvl)						\
+  if (VCL_DBG_ON && vcm->debug > _lvl)					\
     clib_warning ("vcl<w%d>: " _fmt, __vcl_worker_index, ##_args)
 
 #define foreach_vcl_dbg_evt						\
diff --git a/src/vcl/vcl_test.h b/src/vcl/vcl_test.h
index 83e63e1a4e7..68750af89a1 100644
--- a/src/vcl/vcl_test.h
+++ b/src/vcl/vcl_test.h
@@ -125,9 +125,7 @@ static inline int
 vcl_test_write (int fd, uint8_t *buf, uint32_t nbytes,
                  sock_test_stats_t *stats, uint32_t verbose)
 {
-  int tx_bytes = 0;
-  int nbytes_left = nbytes;
-  int rv, errno_val;
+  int tx_bytes = 0, nbytes_left = nbytes, rv;
 
   do
     {
@@ -163,10 +161,7 @@ vcl_test_write (int fd, uint8_t *buf, uint32_t nbytes,
 
   if (tx_bytes < 0)
     {
-      errno_val = errno;
-      perror ("ERROR in sock_test_write()");
-      fprintf (stderr, "SOCK_TEST: ERROR: socket write failed "
-               "(errno = %d)!\n", errno_val);
+      vterr ("vpcom_session_write", -errno);
     }
   else if (stats)
     stats->tx_bytes += tx_bytes;
diff --git a/src/vcl/vppcom.c b/src/vcl/vppcom.c
index cf3a770f045..16b467f5a36 100644
--- a/src/vcl/vppcom.c
+++ b/src/vcl/vppcom.c
@@ -1511,6 +1511,7 @@ vppcom_session_write (uint32_t session_handle, void *buf, size_t n)
   svm_msg_q_msg_t msg;
   session_event_t *e;
   svm_msg_q_t *mq;
+  u8 is_ct;
 
   if (PREDICT_FALSE (!buf))
     return VPPCOM_EINVAL;
@@ -1519,9 +1520,6 @@ vppcom_session_write (uint32_t session_handle, void *buf, size_t n)
   if (PREDICT_FALSE (!s))
     return VPPCOM_EBADFD;
 
-  tx_fifo = s->tx_fifo;
-  is_nonblocking = VCL_SESS_ATTR_TEST (s->attr, VCL_SESS_ATTR_NONBLOCK);
-
   if (PREDICT_FALSE (s->is_vep))
     {
       clib_warning ("VCL<%d>: ERROR: vpp handle 0x%llx, sid %u: "
@@ -1531,18 +1529,20 @@ vppcom_session_write (uint32_t session_handle, void *buf, size_t n)
       return VPPCOM_EBADFD;
     }
 
-  if (!(s->session_state & STATE_OPEN))
+  if (PREDICT_FALSE (!(s->session_state & STATE_OPEN)))
     {
       session_state_t state = s->session_state;
       rv = ((state & STATE_DISCONNECT) ? VPPCOM_ECONNRESET : VPPCOM_ENOTCONN);
       VDBG (1, "VCL<%d>: vpp handle 0x%llx, sid %u: session is not open! "
-	    "state 0x%x (%s)",
-	    getpid (), s->vpp_handle, session_handle,
+	    "state 0x%x (%s)", getpid (), s->vpp_handle, session_handle,
 	    state, vppcom_session_state_str (state));
       return rv;
     }
 
-  mq = vcl_session_is_ct (s) ? s->our_evt_q : wrk->app_event_queue;
+  tx_fifo = s->tx_fifo;
+  is_ct = vcl_session_is_ct (s);
+  is_nonblocking = VCL_SESS_ATTR_TEST (s->attr, VCL_SESS_ATTR_NONBLOCK);
+  mq = is_ct ? s->our_evt_q : wrk->app_event_queue;
   if (svm_fifo_is_full (tx_fifo))
     {
       if (is_nonblocking)
@@ -1551,15 +1551,15 @@ vppcom_session_write (uint32_t session_handle, void *buf, size_t n)
 	}
       while (svm_fifo_is_full (tx_fifo))
 	{
+	  svm_fifo_set_want_tx_evt (tx_fifo, 1);
 	  svm_msg_q_lock (mq);
-	  while (svm_msg_q_is_empty (mq) && svm_msg_q_timedwait (mq, 10e-6))
-	    ;
+	  svm_msg_q_wait (mq);
+
 	  svm_msg_q_sub_w_lock (mq, &msg);
 	  e = svm_msg_q_msg_data (mq, &msg);
 	  svm_msg_q_unlock (mq);
 
-	  if (!vcl_is_tx_evt_for_session (e, s->session_index,
-					  s->our_evt_q != 0))
+	  if (!vcl_is_tx_evt_for_session (e, s->session_index, is_ct))
 	    vcl_handle_mq_event (wrk, e);
 	  svm_msg_q_free_msg (mq, &msg);
 	}
@@ -1576,17 +1576,9 @@ vppcom_session_write (uint32_t session_handle, void *buf, size_t n)
 
   ASSERT (n_write > 0);
 
-  if (VPPCOM_DEBUG > 2)
-    {
-      if (n_write <= 0)
-	clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: "
-		      "FIFO-FULL (%p)", getpid (), s->vpp_handle,
-		      session_handle, tx_fifo);
-      else
-	clib_warning ("VCL<%d>: vpp handle 0x%llx, sid %u: "
-		      "wrote %d bytes tx-fifo: (%p)", getpid (),
-		      s->vpp_handle, session_handle, n_write, tx_fifo);
-    }
+  VDBG (2, "VCL<%d>: vpp handle 0x%llx, sid %u: wrote %d bytes", getpid (),
+	s->vpp_handle, session_handle, n_write);
+
   return n_write;
 }
 
diff --git a/src/vnet/session/session_node.c b/src/vnet/session/session_node.c
index f5aed7490ea..e2a6f4c67c6 100644
--- a/src/vnet/session/session_node.c
+++ b/src/vnet/session/session_node.c
@@ -817,7 +817,7 @@ skip_dequeue:
     {
       stream_session_t *s;	/* $$$ prefetch 1 ahead maybe */
       session_event_t *e;
-      u8 is_full;
+      u8 want_tx_evt;
 
       e = &fifo_events[i];
       switch (e->event_type)
@@ -836,18 +836,19 @@ skip_dequeue:
 	      clib_warning ("It's dead, Jim!");
 	      continue;
 	    }
-	  is_full = svm_fifo_is_full (s->server_tx_fifo);
 
+	  want_tx_evt = svm_fifo_want_tx_evt (s->server_tx_fifo);
 	  /* Spray packets in per session type frames, since they go to
 	   * different nodes */
 	  rv = (smm->session_tx_fns[s->session_type]) (vm, node, e, s,
 						       &n_tx_packets);
 	  if (PREDICT_TRUE (rv == SESSION_TX_OK))
 	    {
-	      /* Notify app there's tx space if not polling */
-	      if (PREDICT_FALSE (is_full
-				 && !svm_fifo_has_event (s->server_tx_fifo)))
-		session_dequeue_notify (s);
+	      if (PREDICT_FALSE (want_tx_evt))
+		{
+		  svm_fifo_set_want_tx_evt (s->server_tx_fifo, 0);
+		  session_dequeue_notify (s);
+		}
 	    }
 	  else if (PREDICT_FALSE (rv == SESSION_TX_NO_BUFFERS))
 	    {