Revised thread/timer handling, work queue and scheduling.

Updated quagga thread handling to use qtimers when using the new
qpnexus -- so all timers are qtimers in the new scheme.

Updated work queue handling so that each work queue item is a single
malloced structure, not three.  (Only bgpd and zebra use the work
queue system.)

When using qpnexus the background thread queue is no longer a timer
queue, but simply a list of pending background threads.  When a
background thread is waiting on a timer, it is in the qtimer pile,
same like any other thread.

When using qpnexus, the only remaining quagga thread queues are the
event and ready queues.

Revised the qpnexus loop so that only when there is nothing else to
do will it consider the background threads.

Revised write I/O in the BGP Engine so that all writing is via the
connection's write buffer.  Revised the write I/O in the Routeing
Engine, so that it passes groups of updates in a single mqueue
message.  This all reduces the number of TCP packets sent (because
BGP messages are collected together in the connection's write buffer)
and reduces the number of mqueue messages involved.
(No need for TCP_CORK.)

Code and comments review for the new code.

  modified:   bgpd/bgp_advertise.c
  modified:   bgpd/bgp_common.h
  modified:   bgpd/bgp_connection.c
  modified:   bgpd/bgp_connection.h
  modified:   bgpd/bgp_engine.h
  modified:   bgpd/bgp_fsm.c
  modified:   bgpd/bgp_main.c
  modified:   bgpd/bgp_msg_read.c
  modified:   bgpd/bgp_msg_write.c
  modified:   bgpd/bgp_network.c
  modified:   bgpd/bgp_packet.c
  modified:   bgpd/bgp_packet.h
  modified:   bgpd/bgp_peer.c
  modified:   bgpd/bgp_peer_index.h
  modified:   bgpd/bgp_route.c
  modified:   bgpd/bgp_route_refresh.h
  modified:   bgpd/bgp_session.c
  modified:   bgpd/bgp_session.h
  modified:   bgpd/bgpd.c
  new file:   bgpd/bgpd.cx
  modified:   lib/mqueue.h
  modified:   lib/qpnexus.c
  modified:   lib/qpnexus.h
  modified:   lib/qpselect.c
  modified:   lib/qtimers.c
  modified:   lib/qtimers.h
  modified:   lib/sigevent.c
  modified:   lib/stream.c
  modified:   lib/stream.h
  modified:   lib/thread.c
  modified:   lib/thread.h
  modified:   lib/workqueue.c
  modified:   lib/workqueue.h
  modified:   tests/heavy-wq.c
  modified:   zebra/zebra_rib.c

1 files changed, 26 insertions, 4 deletions

diff --git a/bgpd/bgp_peer.c b/bgpd/bgp_peer.c
index e6be06c7..16ec8bd9 100644
--- a/bgpd/bgp_peer.c
+++ b/bgpd/bgp_peer.c
@@ -202,6 +202,7 @@ bgp_session_has_established(bgp_peer peer)
   bgp_notify_unset(&(peer->session->notification));
 
   /* Clear start timer value to default. */
+  /* TODO: figure out where to increase the IdleHoldTimer               */
   peer->v_start = BGP_INIT_START_TIMER;
 
   /* Increment established count. */
@@ -547,7 +548,9 @@ bgp_timer_set (struct peer *peer)
 static int
 bgp_routeadv_timer (struct thread *thread)
 {
-  struct peer *peer;
+  struct   peer *peer;
+  uint32_t jittered ;
+  uint32_t jitter ;
 
   peer = THREAD_ARG (thread);
   peer->t_routeadv = NULL;
@@ -559,10 +562,21 @@ bgp_routeadv_timer (struct thread *thread)
 
   peer->synctime = time (NULL);
 
-  bgp_write(peer);
+  bgp_write(peer, NULL);
+
+  /* Apply +/- 10% jitter to the route advertise timer.
+   *
+   * The time is in seconds, so for anything less than 10 seconds this forced
+   * to be +/- 1 second.
+   */
+  jittered = jitter = peer->v_routeadv ;
+  if (jitter < 10)
+    jitter = 10 ;
+  jittered = (jittered * 90) + (rand() % (jitter * 20)) ; /* jitter is +/-10% */
+  jittered = (jittered + 50) / 100 ;
 
-  BGP_TIMER_ON (peer->t_routeadv, bgp_routeadv_timer,
-		peer->v_routeadv);
+  /* TODO: move this to the Routeing Engine qtimer pile.                */
+  BGP_TIMER_ON (peer->t_routeadv, bgp_routeadv_timer, jittered) ;
 
   return 0;
 }
@@ -1023,7 +1037,15 @@ void
 bgp_peer_disable(bgp_peer peer, bgp_notify notification)
 {
   if (bgp_session_is_active(peer->session))
+    {
+      /* This code has been moved from where it was, in bgp_write       */
+      /* TODO: not clear whether v_start handling is still correct      */
+      peer->v_start *= 2;
+      if (peer->v_start >= (60 * 2))
+        peer->v_start = (60 * 2);
+
       bgp_session_disable(peer, notification);
+    }
   else
     {
       bgp_notify_free(notification) ;