tcp: compute snd time for rate sample

Type: feature

Change-Id: I6bd675dc28dbc34293e895911efe986844c0564f
Signed-off-by: Florin Coras <fcoras@cisco.com>
(cherry picked from commit 7436b436733ea7217e745f3cc9971aaff1e3dfa4)

2 files changed, 11 insertions, 6 deletions

diff --git a/src/vnet/tcp/tcp.h b/src/vnet/tcp/tcp.h
index 4c4a9a525af..227b3f8a856 100644
--- a/src/vnet/tcp/tcp.h
+++ b/src/vnet/tcp/tcp.h
@@ -240,7 +240,7 @@ typedef struct tcp_bt_sample_
   u64 delivered;		/**< Total delivered bytes for sample */
   f64 delivered_time;		/**< Delivered time when sample taken */
   f64 tx_time;			/**< Transmit time for the burst */
-  u64 tx_rate;			/**< Tx pacing rate */
+  f64 first_tx_time;		/**< Connection first tx time at tx */
   tcp_bts_flags_t flags;	/**< Sample flag */
 } tcp_bt_sample_t;
 
@@ -251,7 +251,6 @@ typedef struct tcp_rate_sample_
   f64 prior_time;		/**< Delivered time of sample used for rate */
   f64 interval_time;		/**< Time to ack the bytes delivered */
   f64 rtt_time;			/**< RTT for sample */
-  u64 tx_rate;			/**< Tx pacing rate */
   u32 delivered;		/**< Bytes delivered in interval_time */
   u32 acked_and_sacked;		/**< Bytes acked + sacked now */
   u32 lost;			/**< Bytes lost now */
@@ -394,6 +393,7 @@ typedef struct _tcp_connection
   u64 delivered;		/**< Total bytes delivered to peer */
   u64 app_limited;		/**< Delivered when app-limited detected */
   f64 delivered_time;		/**< Time last bytes were acked */
+  f64 first_tx_time;		/**< Send time for recently delivered/sent */
   tcp_byte_tracker_t *bt;	/**< Tx byte tracker */
 
   tcp_errors_t errors;	/**< Soft connection errors */
diff --git a/src/vnet/tcp/tcp_bt.c b/src/vnet/tcp/tcp_bt.c
index fe007543cd0..b550fdd65dd 100644
--- a/src/vnet/tcp/tcp_bt.c
+++ b/src/vnet/tcp/tcp_bt.c
@@ -241,8 +241,8 @@ tcp_bt_alloc_tx_sample (tcp_connection_t * tc, u32 min_seq)
   bts = bt_alloc_sample (tc->bt, min_seq);
   bts->delivered = tc->delivered;
   bts->delivered_time = tc->delivered_time;
-  bts->tx_rate = transport_connection_tx_pacer_rate (&tc->connection);
   bts->tx_time = tcp_time_now_us (tc->c_thread_index);
+  bts->first_tx_time = tc->first_tx_time;
   bts->flags |= tc->app_limited ? TCP_BTS_IS_APP_LIMITED : 0;
   return bts;
 }
@@ -270,7 +270,10 @@ tcp_bt_track_tx (tcp_connection_t * tc)
   u32 bts_index;
 
   if (tc->snd_una == tc->snd_nxt)
-    tc->delivered_time = tcp_time_now_us (tc->c_thread_index);
+    {
+      tc->delivered_time = tcp_time_now_us (tc->c_thread_index);
+      tc->first_tx_time = tc->delivered_time;
+    }
 
   bts = tcp_bt_alloc_tx_sample (tc, tc->snd_nxt);
   bts_index = bt_sample_index (bt, bts);
@@ -421,9 +424,10 @@ tcp_bt_sample_to_rate_sample (tcp_connection_t * tc, tcp_bt_sample_t * bts,
 
   rs->prior_delivered = bts->delivered;
   rs->prior_time = bts->delivered_time;
+  rs->interval_time = bts->tx_time - bts->first_tx_time;
   rs->rtt_time = bts->tx_time;
-  rs->tx_rate = bts->tx_rate;
   rs->flags = bts->flags;
+  tc->first_tx_time = bts->tx_time;
 }
 
 static void
@@ -529,7 +533,8 @@ tcp_bt_sample_delivery_rate (tcp_connection_t * tc, tcp_rate_sample_t * rs)
   if (tc->sack_sb.last_sacked_bytes)
     tcp_bt_walk_samples_ooo (tc, rs);
 
-  rs->interval_time = tc->delivered_time - rs->prior_time;
+  rs->interval_time = clib_max (tc->delivered_time - rs->prior_time,
+				rs->interval_time);
   rs->delivered = tc->delivered - rs->prior_delivered;
   rs->rtt_time = tc->delivered_time - rs->rtt_time;
   rs->acked_and_sacked = delivered;