TCP: Update time_now once per burst

Change-Id: I58089d7a9867ede9d8a36b2aea62edef04cb5b81
Signed-off-by: Florin Coras <fcoras@cisco.com>

4 files changed, 15 insertions, 3 deletions

diff --git a/src/vnet/tcp/tcp.c b/src/vnet/tcp/tcp.c
index 4652618b..10ecf2f3 100644
--- a/src/vnet/tcp/tcp.c
+++ b/src/vnet/tcp/tcp.c
@@ -1299,6 +1299,8 @@ tcp_main_enable (vlib_main_t * vm)
 
   tm->bytes_per_buffer = vlib_buffer_free_list_buffer_size
     (vm, VLIB_BUFFER_DEFAULT_FREE_LIST_INDEX);
+
+  vec_validate (tm->time_now, num_threads - 1);
   return error;
 }
 
diff --git a/src/vnet/tcp/tcp.h b/src/vnet/tcp/tcp.h
index a17262fa..52610ddd 100644
--- a/src/vnet/tcp/tcp.h
+++ b/src/vnet/tcp/tcp.h
@@ -367,6 +367,7 @@ typedef struct _tcp_main
 
   u8 log2_tstamp_clocks_per_tick;
   f64 tstamp_ticks_per_clock;
+  u32 *time_now;
 
   /** per-worker tx buffer free lists */
   u32 **tx_buffers;
@@ -619,12 +620,21 @@ void tcp_update_sack_list (tcp_connection_t * tc, u32 start, u32 end);
 always_inline u32
 tcp_time_now (void)
 {
-  return clib_cpu_time_now () * tcp_main.tstamp_ticks_per_clock;
+  return tcp_main.time_now[vlib_get_thread_index ()];
+}
+
+always_inline u32
+tcp_set_time_now (u32 thread_index)
+{
+  tcp_main.time_now[thread_index] = clib_cpu_time_now ()
+    * tcp_main.tstamp_ticks_per_clock;
+  return tcp_main.time_now[thread_index];
 }
 
 always_inline void
 tcp_update_time (f64 now, u32 thread_index)
 {
+  tcp_set_time_now (thread_index);
   tw_timer_expire_timers_16t_2w_512sl (&tcp_main.timer_wheels[thread_index],
 				       now);
   tcp_flush_frames_to_output (thread_index);
diff --git a/src/vnet/tcp/tcp_input.c b/src/vnet/tcp/tcp_input.c
index a3b48d83..2d36c85e 100644
--- a/src/vnet/tcp/tcp_input.c
+++ b/src/vnet/tcp/tcp_input.c
@@ -2801,8 +2801,8 @@ tcp46_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
 
   from = vlib_frame_vector_args (from_frame);
   n_left_from = from_frame->n_vectors;
-
   next_index = node->cached_next_index;
+  tcp_set_time_now (my_thread_index);
 
   while (n_left_from > 0)
     {
diff --git a/src/vnet/tcp/tcp_output.c b/src/vnet/tcp/tcp_output.c
index 4c1add21..5a395b9f 100644
--- a/src/vnet/tcp/tcp_output.c
+++ b/src/vnet/tcp/tcp_output.c
@@ -1621,8 +1621,8 @@ tcp46_output_inline (vlib_main_t * vm,
 
   from = vlib_frame_vector_args (from_frame);
   n_left_from = from_frame->n_vectors;
-
   next_index = node->cached_next_index;
+  tcp_set_time_now (my_thread_index);
 
   while (n_left_from > 0)
     {