session tls: improve app transports tx scheduling

Type: improvement

- allow apps to request rescheduling of tx events via
SESSION_F_CUSTOM_TX flag
- limit max burst per session custom tx dispatch

In tls
- use the new infra to reschedule tx events
- use max burst bytes as upper limit to number of bytes to be encrypted

Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: I544a5a3337af7ebdff3406b776adf30cf96ebf3c

7 files changed, 54 insertions, 35 deletions

diff --git a/src/plugins/tlsmbedtls/tls_mbedtls.c b/src/plugins/tlsmbedtls/tls_mbedtls.c
index 7b722faf822..8ac736ae6f3 100644
--- a/src/plugins/tlsmbedtls/tls_mbedtls.c
+++ b/src/plugins/tlsmbedtls/tls_mbedtls.c
@@ -431,7 +431,7 @@ mbedtls_ctx_handshake_rx (tls_ctx_t * ctx)
 }
 
 static int
-mbedtls_ctx_write (tls_ctx_t * ctx, session_t * app_session)
+mbedtls_ctx_write (tls_ctx_t * ctx, session_t * app_session, u32 max_write)
 {
   mbedtls_ctx_t *mc = (mbedtls_ctx_t *) ctx;
   u8 thread_index = ctx->c_thread_index;
@@ -446,13 +446,14 @@ mbedtls_ctx_write (tls_ctx_t * ctx, session_t * app_session)
   if (!deq_max)
     return 0;
 
+  deq_max = clib_min (deq_max, max_write);
   tls_session = session_get_from_handle (ctx->tls_session_handle);
   enq_max = svm_fifo_max_enqueue_prod (tls_session->tx_fifo);
   deq_now = clib_min (deq_max, TLS_CHUNK_SIZE);
 
   if (PREDICT_FALSE (enq_max == 0))
     {
-      tls_add_vpp_q_builtin_tx_evt (app_session);
+      app_session->flags |= SESSION_F_CUSTOM_TX;
       return 0;
     }
 
@@ -462,7 +463,7 @@ mbedtls_ctx_write (tls_ctx_t * ctx, session_t * app_session)
   wrote = mbedtls_ssl_write (&mc->ssl, mm->tx_bufs[thread_index], deq_now);
   if (wrote <= 0)
     {
-      tls_add_vpp_q_builtin_tx_evt (app_session);
+      app_session->flags |= SESSION_F_CUSTOM_TX;
       return 0;
     }
 
@@ -471,7 +472,7 @@ mbedtls_ctx_write (tls_ctx_t * ctx, session_t * app_session)
   tls_add_vpp_q_tx_evt (tls_session);
 
   if (deq_now < deq_max)
-    tls_add_vpp_q_builtin_tx_evt (app_session);
+    app_session->flags |= SESSION_F_CUSTOM_TX;
 
   return 0;
 }
diff --git a/src/plugins/tlsopenssl/tls_openssl.c b/src/plugins/tlsopenssl/tls_openssl.c
index 43bb13ff967..935e0147e30 100644
--- a/src/plugins/tlsopenssl/tls_openssl.c
+++ b/src/plugins/tlsopenssl/tls_openssl.c
@@ -413,7 +413,7 @@ openssl_confirm_app_close (tls_ctx_t * ctx)
 }
 
 static inline int
-openssl_ctx_write (tls_ctx_t * ctx, session_t * app_session)
+openssl_ctx_write (tls_ctx_t * ctx, session_t * app_session, u32 max_write)
 {
   openssl_ctx_t *oc = (openssl_ctx_t *) ctx;
   int wrote = 0, read, max_buf = 4 * TLS_CHUNK_SIZE, max_space;
@@ -427,6 +427,8 @@ openssl_ctx_write (tls_ctx_t * ctx, session_t * app_session)
   if (!deq_max)
     goto check_tls_fifo;
 
+  deq_max = clib_min (deq_max, max_write);
+
   /* Figure out how much data to write */
   max_space = max_buf - BIO_ctrl_pending (oc->rbio);
   max_space = (max_space < 0) ? 0 : max_space;
@@ -434,17 +436,11 @@ openssl_ctx_write (tls_ctx_t * ctx, session_t * app_session)
 
   wrote = openssl_write_from_fifo_into_ssl (f, oc->ssl, to_write);
   if (!wrote)
-    {
-      tls_add_vpp_q_builtin_tx_evt (app_session);
-      goto check_tls_fifo;
-    }
+    goto check_tls_fifo;
 
   if (svm_fifo_needs_deq_ntf (f, wrote))
     session_dequeue_notify (app_session);
 
-  if (svm_fifo_max_dequeue_cons (f))
-    tls_add_vpp_q_builtin_tx_evt (app_session);
-
 check_tls_fifo:
 
   if (BIO_ctrl_pending (oc->rbio) <= 0)
@@ -455,14 +451,15 @@ check_tls_fifo:
   read = openssl_read_from_bio_into_fifo (tls_session->tx_fifo, oc->rbio);
   if (!read)
     {
-      tls_add_vpp_q_builtin_tx_evt (app_session);
+      /* Request tx reschedule of the app session */
+      app_session->flags |= SESSION_F_CUSTOM_TX;
       return wrote;
     }
 
   tls_add_vpp_q_tx_evt (tls_session);
 
   if (BIO_ctrl_pending (oc->rbio) > 0)
-    tls_add_vpp_q_builtin_tx_evt (app_session);
+    app_session->flags |= SESSION_F_CUSTOM_TX;
   else if (ctx->app_closed)
     openssl_confirm_app_close (ctx);
 
diff --git a/src/plugins/tlspicotls/tls_picotls.c b/src/plugins/tlspicotls/tls_picotls.c
index 17834e3e051..a9eea333779 100644
--- a/src/plugins/tlspicotls/tls_picotls.c
+++ b/src/plugins/tlspicotls/tls_picotls.c
@@ -410,7 +410,7 @@ picotls_content_process (picotls_ctx_t * ptls_ctx, svm_fifo_t * src_fifo,
 }
 
 static inline int
-picotls_ctx_write (tls_ctx_t * ctx, session_t * app_session)
+picotls_ctx_write (tls_ctx_t * ctx, session_t * app_session, u32 max_write)
 {
   picotls_ctx_t *ptls_ctx = (picotls_ctx_t *) ctx;
   u32 deq_max, deq_now;
@@ -457,13 +457,15 @@ picotls_ctx_write (tls_ctx_t * ctx, session_t * app_session)
   deq_max = svm_fifo_max_dequeue_cons (app_tx_fifo);
   if (!deq_max)
     return deq_max;
+
+  deq_max = clib_min (deq_max, max_write);
   deq_now = clib_min (deq_max, svm_fifo_max_read_chunk (app_tx_fifo));
 
   enq_max = svm_fifo_max_enqueue_prod (tls_tx_fifo);
     /** There is no engough enqueue space for one record **/
   if (enq_max <= record_overhead)
     {
-      tls_add_vpp_q_builtin_tx_evt (app_session);
+      app_session->flags |= SESSION_F_CUSTOM_TX;
       return 0;
     }
 
@@ -506,7 +508,7 @@ picotls_ctx_write (tls_ctx_t * ctx, session_t * app_session)
     tls_add_vpp_q_tx_evt (tls_session);
 
   if (from_app_len < deq_max || TLS_WRITE_IS_LEFT (ptls_ctx))
-    tls_add_vpp_q_builtin_tx_evt (app_session);
+    app_session->flags |= SESSION_F_CUSTOM_TX;
 
   if (ctx->app_closed)
     picotls_app_close (ctx);
diff --git a/src/vnet/session/session_node.c b/src/vnet/session/session_node.c
index c2a6ec921af..30eca1e6577 100644
--- a/src/vnet/session/session_node.c
+++ b/src/vnet/session/session_node.c
@@ -1066,15 +1066,37 @@ session_tx_fifo_dequeue_and_snd (session_worker_t * wrk,
 int
 session_tx_fifo_dequeue_internal (session_worker_t * wrk,
 				  vlib_node_runtime_t * node,
-				  session_evt_elt_t * e, int *n_tx_packets)
+				  session_evt_elt_t * elt, int *n_tx_packets)
 {
   session_t *s = wrk->ctx.s;
+  u32 n_packets, max_pkts;
 
   if (PREDICT_FALSE (s->session_state >= SESSION_STATE_TRANSPORT_CLOSED))
     return 0;
-  svm_fifo_unset_event (s->tx_fifo);
-  return transport_custom_tx (session_get_transport_proto (s), s,
-			      VLIB_FRAME_SIZE - *n_tx_packets);
+
+  /* Clear custom-tx flag used to request reschedule for tx */
+  s->flags &= ~SESSION_F_CUSTOM_TX;
+
+  max_pkts = clib_min (VLIB_FRAME_SIZE - *n_tx_packets,
+		       TRANSPORT_PACER_MAX_BURST_PKTS);
+  n_packets = transport_custom_tx (session_get_transport_proto (s), s,
+				   max_pkts);
+  *n_tx_packets -= n_packets;
+
+  if (svm_fifo_max_dequeue_cons (s->tx_fifo)
+      || (s->flags & SESSION_F_CUSTOM_TX))
+    {
+      session_evt_add_old (wrk, elt);
+    }
+  else
+    {
+      svm_fifo_unset_event (s->tx_fifo);
+      if (svm_fifo_max_dequeue_cons (s->tx_fifo))
+	if (svm_fifo_set_event (s->tx_fifo))
+	  session_evt_add_head_old (wrk, elt);
+    }
+
+  return n_packets;
 }
 
 always_inline session_t *
diff --git a/src/vnet/session/transport.h b/src/vnet/session/transport.h
index 53a0dd6c14e..6dc6984cdf4 100644
--- a/src/vnet/session/transport.h
+++ b/src/vnet/session/transport.h
@@ -22,6 +22,7 @@
 #define TRANSPORT_PACER_MIN_MSS 	1460
 #define TRANSPORT_PACER_MIN_BURST 	TRANSPORT_PACER_MIN_MSS
 #define TRANSPORT_PACER_MAX_BURST	(43 * TRANSPORT_PACER_MIN_MSS)
+#define TRANSPORT_PACER_MAX_BURST_PKTS	43
 #define TRANSPORT_PACER_MIN_IDLE	100
 #define TRANSPORT_PACER_IDLE_FACTOR	0.05
 
diff --git a/src/vnet/tls/tls.c b/src/vnet/tls/tls.c
index 7a172b88928..d0552dc6f3b 100644
--- a/src/vnet/tls/tls.c
+++ b/src/vnet/tls/tls.c
@@ -74,15 +74,6 @@ tls_add_vpp_q_tx_evt (session_t * s)
   return 0;
 }
 
-int
-tls_add_vpp_q_builtin_tx_evt (session_t * s)
-{
-  if (svm_fifo_set_event (s->tx_fifo))
-    session_send_io_evt_to_thread_custom (s, s->thread_index,
-					  SESSION_IO_EVT_BUILTIN_TX);
-  return 0;
-}
-
 static inline int
 tls_add_app_q_evt (app_worker_t * app, session_t * app_session)
 {
@@ -316,9 +307,14 @@ tls_ctx_init_client (tls_ctx_t * ctx)
 }
 
 static inline int
-tls_ctx_write (tls_ctx_t * ctx, session_t * app_session)
+tls_ctx_write (tls_ctx_t * ctx, session_t * app_session, u32 max_burst_size)
 {
-  return tls_vfts[ctx->tls_ctx_engine].ctx_write (ctx, app_session);
+  u32 max_write, n_wrote;
+
+  max_write = max_burst_size * TRANSPORT_PACER_MIN_MSS;
+  n_wrote = tls_vfts[ctx->tls_ctx_engine].ctx_write (ctx, app_session,
+						     max_write);
+  return n_wrote > 0 ? clib_max (n_wrote / TRANSPORT_PACER_MIN_MSS, 1) : 0;
 }
 
 static inline int
@@ -726,7 +722,7 @@ tls_custom_tx_callback (void *session, u32 max_burst_size)
     return 0;
 
   ctx = tls_ctx_get (app_session->connection_index);
-  tls_ctx_write (ctx, app_session);
+  tls_ctx_write (ctx, app_session, max_burst_size);
   return 0;
 }
 
@@ -890,7 +886,7 @@ tls_init (vlib_main_t * vm)
 {
   u32 add_segment_size = 256 << 20, first_seg_size = 32 << 20;
   vlib_thread_main_t *vtm = vlib_get_thread_main ();
-  u32 num_threads, fifo_size = 128 << 10;
+  u32 num_threads, fifo_size = 128 << 12;
   vnet_app_attach_args_t _a, *a = &_a;
   u64 options[APP_OPTIONS_N_OPTIONS];
   tls_main_t *tm = &tls_main;
diff --git a/src/vnet/tls/tls.h b/src/vnet/tls/tls.h
index 1281e3d62c9..2d09b291aa7 100644
--- a/src/vnet/tls/tls.h
+++ b/src/vnet/tls/tls.h
@@ -110,7 +110,7 @@ typedef struct tls_engine_vft_
   int (*ctx_init_client) (tls_ctx_t * ctx);
   int (*ctx_init_server) (tls_ctx_t * ctx);
   int (*ctx_read) (tls_ctx_t * ctx, session_t * tls_session);
-  int (*ctx_write) (tls_ctx_t * ctx, session_t * app_session);
+  int (*ctx_write) (tls_ctx_t * ctx, session_t * app_session, u32 max_write);
     u8 (*ctx_handshake_is_over) (tls_ctx_t * ctx);
   int (*ctx_start_listen) (tls_ctx_t * ctx);
   int (*ctx_stop_listen) (tls_ctx_t * ctx);