commit c31dc31f84961033ecb6354811e0c360b6cf5f79
author Florin Coras <fcoras@cisco.com> Sun Oct 06 14:06:14 2019 -0700
committer Florin Coras <florin.coras@gmail.com> Thu Oct 10 21:23:14 2019 +0000
tree 46224d5f2b9d126cb6bd5fa289a18186cb172aa5
parent 71a5da0c8dfa12ff012c8c101cf4d2b29fa0b6e3

tcp: improve pacing after idle send periods

Rest pacer on ack reception if we haven't recently sent anything.

Type: feature

Change-Id: I820bacd81b65130052dfafbfcbe6ca4553069fbc
Signed-off-by: Florin Coras <fcoras@cisco.com>

src/vnet/session/transport.c

diff --git a/src/vnet/session/transport.c b/src/vnet/session/transport.c
index 49a4af7..8f7e30c 100644
--- a/src/vnet/session/transport.c
+++ b/src/vnet/session/transport.c
@@ -47,10 +47,6 @@
  */
 static double transport_pacer_period;
 
-#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)
-
 u8 *
 format_transport_proto (u8 * s, va_list * args)
 {
@@ -583,6 +579,13 @@
   u64 n_periods = norm_time_now - pacer->last_update;
   u64 inc;
 
+  if (PREDICT_FALSE (n_periods > 5e5))
+    {
+      pacer->last_update = norm_time_now;
+      pacer->bucket = TRANSPORT_PACER_MIN_BURST;
+      return TRANSPORT_PACER_MIN_BURST;
+    }
+
   if (n_periods > 0
       && (inc = (f32) n_periods * pacer->tokens_per_period) > 10)
     {
@@ -674,7 +677,7 @@
   u32 snd_space, max_paced_burst;
 
   snd_space = tp_vfts[tc->proto].send_space (tc);
-  if (transport_connection_is_tx_paced (tc))
+  if (snd_space && transport_connection_is_tx_paced (tc))
     {
       time_now >>= SPACER_CPU_TICKS_PER_PERIOD_SHIFT;
       max_paced_burst = spacer_max_burst (&tc->pacer, time_now);