commit 0f8b91f5d8e4bc2f9a0166440abaf00b2bda29bb
author Florin Coras <fcoras@cisco.com> Wed Jan 05 08:47:11 2022 -0800
committer Florin Coras <florin.coras@gmail.com> Thu Jan 06 20:18:53 2022 +0000
tree ff5c4e458895bdd96a7ee20f285e9035df203e44
parent 273968cf2d0343b2f4e3217f25c0752f20cf03c5

tcp: use bytes delivered to compute cwnd

Should estimated cwnd better with loss

Type: improvement

Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: Idd75d40dbab212ac0a5d533009c5540b1a58f4c4

src/vnet/tcp/tcp_cubic.c

diff --git a/src/vnet/tcp/tcp_cubic.c b/src/vnet/tcp/tcp_cubic.c
index cc2ffea..3160e52 100644
--- a/src/vnet/tcp/tcp_cubic.c
+++ b/src/vnet/tcp/tcp_cubic.c
@@ -158,7 +158,7 @@
 
   if (tcp_in_slowstart (tc))
     {
-      tc->cwnd += tc->bytes_acked;
+      tc->cwnd += rs->delivered;
       return;
     }
 
@@ -169,7 +169,7 @@
   w_aimd = (u64) W_est (cd, t, rtt_sec) * tc->snd_mss;
   if (w_cubic < w_aimd)
     {
-      cubic_cwnd_accumulate (tc, tc->cwnd, tc->bytes_acked);
+      cubic_cwnd_accumulate (tc, tc->cwnd, rs->delivered);
     }
   else
     {
@@ -195,7 +195,7 @@
 	  /* Practically we can't increment so just inflate threshold */
 	  thresh = 50 * tc->cwnd;
 	}
-      cubic_cwnd_accumulate (tc, thresh, tc->bytes_acked);
+      cubic_cwnd_accumulate (tc, thresh, rs->delivered);
     }
 }
 

src/vnet/tcp/tcp_input.c

diff --git a/src/vnet/tcp/tcp_input.c b/src/vnet/tcp/tcp_input.c
index 30d57a3..5f165c0 100644
--- a/src/vnet/tcp/tcp_input.c
+++ b/src/vnet/tcp/tcp_input.c
@@ -866,8 +866,7 @@
 	tcp_fastrecovery_first_on (tc);
 
       tc->rxt_delivered += tc->sack_sb.rxt_sacked;
-      tc->prr_delivered += tc->bytes_acked + tc->sack_sb.last_sacked_bytes
-	- tc->sack_sb.last_bytes_delivered;
+      tc->prr_delivered += rs->delivered;
     }
   else
     {
@@ -1042,6 +1041,9 @@
 
   if (tc->cfg_flags & TCP_CFG_F_RATE_SAMPLE)
     tcp_bt_sample_delivery_rate (tc, &rs);
+  else
+    rs.delivered = tc->bytes_acked + tc->sack_sb.last_sacked_bytes -
+		   tc->sack_sb.last_bytes_delivered;
 
   if (tc->bytes_acked + tc->sack_sb.last_sacked_bytes)
     {

src/vnet/tcp/tcp_newreno.c

diff --git a/src/vnet/tcp/tcp_newreno.c b/src/vnet/tcp/tcp_newreno.c
index c5ffc2a..39035ba 100644
--- a/src/vnet/tcp/tcp_newreno.c
+++ b/src/vnet/tcp/tcp_newreno.c
@@ -49,12 +49,12 @@
 {
   if (tcp_in_slowstart (tc))
     {
-      tc->cwnd += clib_min (tc->snd_mss, tc->bytes_acked);
+      tc->cwnd += clib_min (tc->snd_mss, rs->delivered);
     }
   else
     {
       /* tc->cwnd += clib_max ((tc->snd_mss * tc->snd_mss) / tc->cwnd, 1); */
-      tcp_cwnd_accumulate (tc, tc->cwnd, tc->bytes_acked);
+      tcp_cwnd_accumulate (tc, tc->cwnd, rs->delivered);
     }
 }