wireguard: testing alternative timer dispatch

Change-Id: I645bb0a31b333a6160c74987dddb3fb50ff154d8
Type: improvement
Signed-off-by: Mohammed Hawari <mohammed@hawari.fr>

src/plugins/wireguard/wireguard_peer.c

@@ -81,6 +81,7 @@ wg_peer_clear (vlib_main_t * vm, wg_peer_t * peer)
   for (int i = 0; i < WG_N_TIMERS; i++)
     {
       peer->timers[i] = ~0;
+      peer->timers_dispatched[i] = 0;
     }
 
   peer->last_sent_handshake = vlib_time_now (vm) - (REKEY_TIMEOUT + 1);

src/plugins/wireguard/wireguard_peer.h

@@ -71,6 +71,7 @@ typedef struct wg_peer
   /* Timers */
   tw_timer_wheel_16t_2w_512sl_t *timer_wheel;
   u32 timers[WG_N_TIMERS];
+  u8 timers_dispatched[WG_N_TIMERS];
   u32 timer_handshake_attempts;
   u16 persistent_keepalive_interval;
 

src/plugins/wireguard/wireguard_timer.c

@@ -62,7 +62,6 @@ start_timer_thread_fn (void *arg)
 {
   wg_timers_args *a = arg;
   wg_peer_t *peer = wg_peer_get (a->peer_idx);
-
   start_timer (peer, a->timer_id, a->interval_ticks);
   return 0;
 }
@@ -75,8 +74,11 @@ start_timer_from_mt (u32 peer_idx, u32 timer_id, u32 interval_ticks)
     .timer_id = timer_id,
     .interval_ticks = interval_ticks,
   };
-
-  vl_api_rpc_call_main_thread (start_timer_thread_fn, (u8 *) & a, sizeof (a));
+  wg_peer_t *peer = wg_peer_get (peer_idx);
+  if (PREDICT_FALSE (!peer->timers_dispatched[timer_id]))
+    if (!clib_atomic_cmp_and_swap (&peer->timers_dispatched[timer_id], 0, 1))
+      vl_api_rpc_call_main_thread (start_timer_thread_fn, (u8 *) &a,
+				   sizeof (a));
 }
 
 static inline u32
@@ -295,6 +297,9 @@ expired_timer_callback (u32 * expired_timers)
 
       peer = wg_peer_get (pool_index);
       peer->timers[timer_id] = ~0;
+
+      /* Under barrier, no sync needed */
+      peer->timers_dispatched[timer_id] = 0;
     }
 
   for (i = 0; i < vec_len (expired_timers); i++)