X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=src%2Fvnet%2Ftcp%2Ftcp_cubic.c;h=b79ef8342d30f7a0b1fd1e7b342df649ff85f3eb;hb=c30318da220953610820a2e7cd957da7046eaf4b;hp=55bbcca34975e1cedb86361dda90659a9416bc71;hpb=aa01abb2b732abfb44559d25c9a11adfed57ac8b;p=vpp.git

diff --git a/src/vnet/tcp/tcp_cubic.c b/src/vnet/tcp/tcp_cubic.c
index 55bbcca3497..b79ef8342d3 100644
--- a/src/vnet/tcp/tcp_cubic.c
+++ b/src/vnet/tcp/tcp_cubic.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018 Cisco and/or its affiliates.
+ * Copyright (c) 2018-2019 Cisco and/or its affiliates.
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at:
@@ -23,10 +23,12 @@
 typedef struct cubic_cfg_
 {
   u8 fast_convergence;
+  u32 ssthresh;
 } cubic_cfg_t;
 
 static cubic_cfg_t cubic_cfg = {
   .fast_convergence = 1,
+  .ssthresh = 0x7FFFFFFFU,
 };
 
 typedef struct cubic_data_
@@ -69,10 +71,12 @@ W_cubic (cubic_data_t * cd, f64 t)
  * RFC 8312 Eq. 2
  */
 static inline f64
-K_cubic (cubic_data_t * cd)
+K_cubic (cubic_data_t * cd, u32 wnd)
 {
-  /* K = cubic_root(W_max*(1-beta_cubic)/C) */
-  return pow (cd->w_max * (1 - beta_cubic) / cubic_c, 1 / 3.0);
+  /* K = cubic_root(W_max*(1-beta_cubic)/C)
+   * Because the current window may be less than W_max * beta_cubic because
+   * of fast convergence, we pass it as parameter */
+  return pow ((f64) (cd->w_max - wnd) / cubic_c, 1 / 3.0);
 }
 
 /**
@@ -101,6 +105,18 @@ cubic_congestion (tcp_connection_t * tc)
 
   cd->w_max = w_max;
   tc->ssthresh = clib_max (tc->cwnd * beta_cubic, 2 * tc->snd_mss);
+  tc->cwnd = tc->ssthresh;
+}
+
+static void
+cubic_loss (tcp_connection_t * tc)
+{
+  cubic_data_t *cd = (cubic_data_t *) tcp_cc_data (tc);
+
+  tc->cwnd = tcp_loss_wnd (tc);
+  cd->t_start = cubic_time (tc->c_thread_index);
+  cd->K = 0;
+  cd->w_max = tc->cwnd / tc->snd_mss;
 }
 
 static void
@@ -108,12 +124,27 @@ cubic_recovered (tcp_connection_t * tc)
 {
   cubic_data_t *cd = (cubic_data_t *) tcp_cc_data (tc);
   cd->t_start = cubic_time (tc->c_thread_index);
-  cd->K = K_cubic (cd);
   tc->cwnd = tc->ssthresh;
+  cd->K = K_cubic (cd, tc->cwnd / tc->snd_mss);
 }
 
 static void
-cubic_rcv_ack (tcp_connection_t * tc)
+cubic_cwnd_accumulate (tcp_connection_t * tc, u32 thresh, u32 bytes_acked)
+{
+  /* We just updated the threshold and don't know how large the previous
+   * one was. Still, optimistically increase cwnd by one segment and
+   * clear the accumulated bytes. */
+  if (tc->cwnd_acc_bytes > thresh)
+    {
+      tc->cwnd += tc->snd_mss;
+      tc->cwnd_acc_bytes = 0;
+    }
+
+  tcp_cwnd_accumulate (tc, thresh, tc->bytes_acked);
+}
+
+static void
+cubic_rcv_ack (tcp_connection_t * tc, tcp_rate_sample_t * rs)
 {
   cubic_data_t *cd = (cubic_data_t *) tcp_cc_data (tc);
   u64 w_cubic, w_aimd;
@@ -126,7 +157,7 @@ cubic_rcv_ack (tcp_connection_t * tc)
 
   if (tcp_in_slowstart (tc))
     {
-      tc->cwnd += clib_min (tc->snd_mss, tc->bytes_acked);
+      tc->cwnd += tc->bytes_acked;
       return;
     }
 
@@ -137,7 +168,7 @@ cubic_rcv_ack (tcp_connection_t * tc)
   w_aimd = (u64) W_est (cd, t, rtt_sec) * tc->snd_mss;
   if (w_cubic < w_aimd)
     {
-      tcp_cwnd_accumulate (tc, tc->cwnd, tc->bytes_acked);
+      cubic_cwnd_accumulate (tc, tc->cwnd, tc->bytes_acked);
     }
   else
     {
@@ -155,16 +186,15 @@ cubic_rcv_ack (tcp_connection_t * tc)
 	   */
 	  thresh = (tc->snd_mss * tc->cwnd) / (w_cubic - tc->cwnd);
 
-	  /* Make sure we don't increase cwnd more often than every
-	   * 2 segments */
-	  thresh = clib_max (thresh, 2 * tc->snd_mss);
+	  /* Make sure we don't increase cwnd more often than every segment */
+	  thresh = clib_max (thresh, tc->snd_mss);
 	}
       else
 	{
 	  /* Practically we can't increment so just inflate threshold */
 	  thresh = 50 * tc->cwnd;
 	}
-      tcp_cwnd_accumulate (tc, thresh, tc->bytes_acked);
+      cubic_cwnd_accumulate (tc, thresh, tc->bytes_acked);
     }
 }
 
@@ -172,7 +202,7 @@ static void
 cubic_conn_init (tcp_connection_t * tc)
 {
   cubic_data_t *cd = (cubic_data_t *) tcp_cc_data (tc);
-  tc->ssthresh = tc->snd_wnd;
+  tc->ssthresh = cubic_cfg.ssthresh;
   tc->cwnd = tcp_initial_cwnd (tc);
   cd->w_max = 0;
   cd->K = 0;
@@ -182,6 +212,8 @@ cubic_conn_init (tcp_connection_t * tc)
 static uword
 cubic_unformat_config (unformat_input_t * input)
 {
+  u32 ssthresh = 0x7FFFFFFFU;
+
   if (!input)
     return 0;
 
@@ -191,6 +223,8 @@ cubic_unformat_config (unformat_input_t * input)
     {
       if (unformat (input, "no-fast-convergence"))
 	cubic_cfg.fast_convergence = 0;
+      else if (unformat (input, "ssthresh %u", &ssthresh))
+	cubic_cfg.ssthresh = ssthresh;
       else
 	return 0;
     }
@@ -201,6 +235,7 @@ const static tcp_cc_algorithm_t tcp_cubic = {
   .name = "cubic",
   .unformat_cfg = cubic_unformat_config,
   .congestion = cubic_congestion,
+  .loss = cubic_loss,
   .recovered = cubic_recovered,
   .rcv_ack = cubic_rcv_ack,
   .rcv_cong_ack = newreno_rcv_cong_ack,