tcp: avoid sending acks when data available
[vpp.git] / src / vnet / tcp / tcp_output.c
index 79866af..6ba0ee2 100644 (file)
@@ -405,11 +405,14 @@ tcp_update_burst_snd_vars (tcp_connection_t * tc)
 
   tcp_update_rcv_wnd (tc);
 
-  if (tc->flags & TCP_CONN_RATE_SAMPLE)
+  if (tc->cfg_flags & TCP_CFG_F_RATE_SAMPLE)
     tc->flags |= TCP_CONN_TRACK_BURST;
 
   if (tc->snd_una == tc->snd_nxt)
-    tcp_cc_event (tc, TCP_CC_EVT_START_TX);
+    {
+      tcp_cc_event (tc, TCP_CC_EVT_START_TX);
+      tcp_connection_tx_pacer_reset (tc, tc->cwnd, TRANSPORT_PACER_MIN_MSS);
+    }
 }
 
 #endif /* CLIB_MARCH_VARIANT */
@@ -496,7 +499,7 @@ static inline u16
 tcp_compute_checksum (tcp_connection_t * tc, vlib_buffer_t * b)
 {
   u16 checksum = 0;
-  if (PREDICT_FALSE (tc->flags & TCP_CONN_NO_CSUM_OFFLOAD))
+  if (PREDICT_FALSE (tc->cfg_flags & TCP_CFG_F_NO_CSUM_OFFLOAD))
     {
       tcp_worker_ctx_t *wrk = tcp_get_worker (tc->c_thread_index);
       vlib_main_t *vm = wrk->vm;
@@ -515,7 +518,6 @@ tcp_compute_checksum (tcp_connection_t * tc, vlib_buffer_t * b)
   return checksum;
 }
 
-
 /**
  * Prepare ACK
  */
@@ -864,7 +866,7 @@ tcp_send_reset_w_pkt (tcp_connection_t * tc, vlib_buffer_t * pkt,
       ASSERT ((pkt_ih4->ip_version_and_header_length & 0xF0) == 0x40);
       ih4 = vlib_buffer_push_ip4 (vm, b, &pkt_ih4->dst_address,
                                  &pkt_ih4->src_address, IP_PROTOCOL_TCP,
-                                 (!(tc->flags & TCP_CONN_NO_CSUM_OFFLOAD)));
+                                 tcp_csum_offload (tc));
       th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih4);
     }
   else
@@ -931,7 +933,7 @@ tcp_push_ip_hdr (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
       ip4_header_t *ih;
       ih = vlib_buffer_push_ip4 (vm, b, &tc->c_lcl_ip4,
                                 &tc->c_rmt_ip4, IP_PROTOCOL_TCP,
-                                (!(tc->flags & TCP_CONN_NO_CSUM_OFFLOAD)));
+                                tcp_csum_offload (tc));
       th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih);
     }
   else
@@ -1083,6 +1085,10 @@ tcp_send_fin (tcp_connection_t * tc)
       return;
     }
 
+  /* If we have non-dupacks programmed, no need to send them */
+  if ((tc->flags & TCP_CONN_SNDACK) && !tc->pending_dupacks)
+    tc->flags &= ~TCP_CONN_SNDACK;
+
   tcp_retransmit_timer_force_update (tc);
   b = vlib_get_buffer (vm, bi);
   tcp_init_buffer (vm, b);
@@ -1162,7 +1168,6 @@ tcp_push_hdr_i (tcp_connection_t * tc, vlib_buffer_t * b, u32 snd_nxt,
   tc->bytes_out += data_len;
   tc->data_segs_out += 1;
 
-
   th->checksum = tcp_compute_checksum (tc, b);
 
   TCP_EVT (TCP_EVT_PKTIZE, tc);
@@ -1435,26 +1440,14 @@ tcp_prepare_retransmit_segment (tcp_worker_ctx_t * wrk,
   max_deq_bytes = clib_min (tc->snd_mss, max_deq_bytes);
   max_deq_bytes = clib_min (available_bytes, max_deq_bytes);
 
-  /* Start is beyond snd_congestion */
   start = tc->snd_una + offset;
-  if (seq_geq (start, tc->snd_congestion))
-    return 0;
-
-  /* Don't overshoot snd_congestion */
-  if (seq_gt (start + max_deq_bytes, tc->snd_congestion))
-    {
-      max_deq_bytes = tc->snd_congestion - start;
-      if (max_deq_bytes == 0)
-       return 0;
-    }
-
   n_bytes = tcp_prepare_segment (wrk, tc, offset, max_deq_bytes, b);
   if (!n_bytes)
     return 0;
 
   tc->snd_rxt_bytes += n_bytes;
 
-  if (tc->flags & TCP_CONN_RATE_SAMPLE)
+  if (tc->cfg_flags & TCP_CFG_F_RATE_SAMPLE)
     tcp_bt_track_rxt (tc, start, start + n_bytes);
 
   tc->bytes_retrans += n_bytes;
@@ -1786,7 +1779,7 @@ tcp_timer_persist_handler (u32 index)
                           || tc->snd_nxt == tc->snd_una_max
                           || tc->rto_boff > 1));
 
-  if (tc->flags & TCP_CONN_RATE_SAMPLE)
+  if (tc->cfg_flags & TCP_CFG_F_RATE_SAMPLE)
     {
       tcp_bt_check_app_limited (tc);
       tcp_bt_track_tx (tc);
@@ -1892,6 +1885,13 @@ tcp_retransmit_should_retry_head (tcp_connection_t * tc,
   return (tx_adv_sack > (tc->snd_una - tc->prr_start) * rr);
 }
 
+static inline u8
+tcp_max_tx_deq (tcp_connection_t * tc)
+{
+  return (transport_max_tx_dequeue (&tc->connection)
+         - (tc->snd_nxt - tc->snd_una));
+}
+
 #define scoreboard_rescue_rxt_valid(_sb, _tc)                  \
     (seq_geq (_sb->rescue_rxt, _tc->snd_una)                   \
        && seq_leq (_sb->rescue_rxt, _tc->snd_congestion))
@@ -1903,17 +1903,28 @@ static int
 tcp_retransmit_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
                     u32 burst_size)
 {
+  u8 snd_limited = 0, can_rescue = 0, reset_pacer = 0;
   u32 n_written = 0, offset, max_bytes, n_segs = 0;
+  u32 bi, max_deq, burst_bytes, sent_bytes;
   sack_scoreboard_hole_t *hole;
   vlib_main_t *vm = wrk->vm;
   vlib_buffer_t *b = 0;
   sack_scoreboard_t *sb;
-  u32 bi, max_deq;
   int snd_space;
-  u8 snd_limited = 0, can_rescue = 0;
+  u64 time_now;
 
   ASSERT (tcp_in_cong_recovery (tc));
 
+  time_now = wrk->vm->clib_time.last_cpu_time;
+  burst_bytes = transport_connection_tx_pacer_burst (&tc->connection,
+                                                    time_now);
+  burst_size = clib_min (burst_size, burst_bytes / tc->snd_mss);
+  if (!burst_size)
+    {
+      tcp_program_retransmit (tc);
+      return 0;
+    }
+
   if (tcp_in_recovery (tc))
     snd_space = tcp_available_cc_snd_space (tc);
   else
@@ -1921,17 +1932,17 @@ tcp_retransmit_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
 
   if (snd_space < tc->snd_mss)
     {
-      /* We're cc constrained so don't accumulate tokens */
-      transport_connection_tx_pacer_reset_bucket (&tc->connection,
-                                                 vm->
-                                                 clib_time.last_cpu_time);
-      return 0;
+      reset_pacer = burst_bytes > tc->snd_mss;
+      goto done;
     }
 
+  reset_pacer = snd_space < burst_bytes;
+
   sb = &tc->sack_sb;
 
   /* Check if snd_una is a lost retransmit */
-  if (seq_gt (sb->high_sacked, tc->snd_congestion)
+  if (pool_elts (sb->holes)
+      && seq_gt (sb->high_sacked, tc->snd_congestion)
       && tc->rxt_head != tc->snd_una
       && tcp_retransmit_should_retry_head (tc, sb))
     {
@@ -1967,9 +1978,12 @@ tcp_retransmit_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
          /* We are out of lost holes to retransmit so send some new data. */
          if (max_deq > tc->snd_mss)
            {
-             u32 n_segs_new, av_window;
-             av_window = tc->snd_wnd - (tc->snd_nxt - tc->snd_una);
-             snd_space = clib_min (snd_space, av_window);
+             u32 n_segs_new;
+             int av_wnd;
+
+             av_wnd = (int) tc->snd_wnd - (tc->snd_nxt - tc->snd_una);
+             av_wnd = clib_max (av_wnd, 0);
+             snd_space = clib_min (snd_space, av_wnd);
              snd_space = clib_min (max_deq, snd_space);
              burst_size = clib_min (burst_size - n_segs,
                                     snd_space / tc->snd_mss);
@@ -2034,6 +2048,19 @@ tcp_retransmit_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
 
 done:
 
+  if (reset_pacer)
+    {
+      transport_connection_tx_pacer_reset_bucket (&tc->connection,
+                                                 vm->clib_time.
+                                                 last_cpu_time);
+    }
+  else
+    {
+      sent_bytes = clib_min (n_segs * tc->snd_mss, burst_bytes);
+      transport_connection_tx_pacer_update_bytes (&tc->connection,
+                                                 sent_bytes);
+    }
+
   return n_segs;
 }
 
@@ -2045,14 +2072,28 @@ tcp_retransmit_no_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
                        u32 burst_size)
 {
   u32 n_written = 0, offset = 0, bi, max_deq, n_segs_now;
+  u32 burst_bytes, sent_bytes;
   vlib_main_t *vm = wrk->vm;
   int snd_space, n_segs = 0;
+  u8 cc_limited = 0;
   vlib_buffer_t *b;
+  u64 time_now;
 
   ASSERT (tcp_in_fastrecovery (tc));
   TCP_EVT (TCP_EVT_CC_EVT, tc, 0);
 
+  time_now = wrk->vm->clib_time.last_cpu_time;
+  burst_bytes = transport_connection_tx_pacer_burst (&tc->connection,
+                                                    time_now);
+  burst_size = clib_min (burst_size, burst_bytes / tc->snd_mss);
+  if (!burst_size)
+    {
+      tcp_program_retransmit (tc);
+      return 0;
+    }
+
   snd_space = tcp_available_cc_snd_space (tc);
+  cc_limited = snd_space < burst_bytes;
 
   if (!tcp_fastrecovery_first (tc))
     goto send_unsent;
@@ -2098,19 +2139,12 @@ send_unsent:
 
 done:
   tcp_fastrecovery_first_off (tc);
-  return n_segs;
-}
 
-/**
- * Do fast retransmit
- */
-static int
-tcp_retransmit (tcp_worker_ctx_t * wrk, tcp_connection_t * tc, u32 burst_size)
-{
-  if (tcp_opts_sack_permitted (&tc->rcv_opts))
-    return tcp_retransmit_sack (wrk, tc, burst_size);
-  else
-    return tcp_retransmit_no_sack (wrk, tc, burst_size);
+  sent_bytes = clib_min (n_segs * tc->snd_mss, burst_bytes);
+  sent_bytes = cc_limited ? burst_bytes : sent_bytes;
+  transport_connection_tx_pacer_update_bytes (&tc->connection, sent_bytes);
+
+  return n_segs;
 }
 
 static int
@@ -2120,8 +2154,13 @@ tcp_send_acks (tcp_connection_t * tc, u32 max_burst_size)
 
   if (!tc->pending_dupacks)
     {
-      tcp_send_ack (tc);
-      return 1;
+      if (tcp_in_cong_recovery (tc) || !tcp_max_tx_deq (tc)
+         || tc->state != TCP_STATE_ESTABLISHED)
+       {
+         tcp_send_ack (tc);
+         return 1;
+       }
+      return 0;
     }
 
   /* If we're supposed to send dupacks but have no ooo data
@@ -2129,6 +2168,7 @@ tcp_send_acks (tcp_connection_t * tc, u32 max_burst_size)
   if (!vec_len (tc->snd_sacks))
     {
       tcp_send_ack (tc);
+      tc->pending_dupacks = 0;
       return 1;
     }
 
@@ -2164,23 +2204,16 @@ tcp_send_acks (tcp_connection_t * tc, u32 max_burst_size)
 static int
 tcp_do_retransmit (tcp_connection_t * tc, u32 max_burst_size)
 {
-  u32 n_segs = 0, burst_size, sent_bytes, burst_bytes;
   tcp_worker_ctx_t *wrk;
+  u32 n_segs;
 
   wrk = tcp_get_worker (tc->c_thread_index);
-  burst_bytes = transport_connection_tx_pacer_burst (&tc->connection,
-                                                    wrk->vm->
-                                                    clib_time.last_cpu_time);
-  burst_size = clib_min (max_burst_size, burst_bytes / tc->snd_mss);
-  if (!burst_size)
-    {
-      tcp_program_retransmit (tc);
-      return 0;
-    }
 
-  n_segs = tcp_retransmit (wrk, tc, burst_size);
-  sent_bytes = clib_min (n_segs * tc->snd_mss, burst_bytes);
-  transport_connection_tx_pacer_update_bytes (&tc->connection, sent_bytes);
+  if (tcp_opts_sack_permitted (&tc->rcv_opts))
+    n_segs = tcp_retransmit_sack (wrk, tc, max_burst_size);
+  else
+    n_segs = tcp_retransmit_no_sack (wrk, tc, max_burst_size);
+
   return n_segs;
 }
 
@@ -2284,8 +2317,7 @@ tcp_output_push_ip (vlib_main_t * vm, vlib_buffer_t * b0,
 
   if (is_ip4)
     ih0 = vlib_buffer_push_ip4 (vm, b0, &tc0->c_lcl_ip4, &tc0->c_rmt_ip4,
-                               IP_PROTOCOL_TCP,
-                               (!(tc0->flags & TCP_CONN_NO_CSUM_OFFLOAD)));
+                               IP_PROTOCOL_TCP, tcp_csum_offload (tc0));
   else
     ih0 = vlib_buffer_push_ip6 (vm, b0, &tc0->c_lcl_ip6, &tc0->c_rmt_ip6,
                                IP_PROTOCOL_TCP);
@@ -2295,8 +2327,9 @@ tcp_output_push_ip (vlib_main_t * vm, vlib_buffer_t * b0,
 always_inline void
 tcp_check_if_gso (tcp_connection_t * tc, vlib_buffer_t * b)
 {
-  if (!tc->is_tso)
+  if (PREDICT_TRUE (!(tc->cfg_flags & TCP_CFG_F_TSO)))
     return;
+
   u16 data_len = b->current_length - sizeof (tcp_header_t) - tc->snd_opts_len;
 
   if (PREDICT_FALSE (b->flags & VLIB_BUFFER_TOTAL_LENGTH_VALID))