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, 15 insertions, 9 deletions

diff --git a/lib/qtimers.c b/lib/qtimers.c
index dcce24b9..0aef52a4 100644
--- a/lib/qtimers.c
+++ b/lib/qtimers.c
@@ -108,7 +108,9 @@ qtimer_pile_init_new(qtimer_pile qtp)
    *   timers        -- invalid heap -- need to properly initialise
    */
 
-  /* Eclipse flags offsetof(struct qtimer, backlink) as a syntax error :-(  */
+  /* (The typedef is required to stop Eclipse (3.4.2 with CDT 5.0) whining
+   *  about first argument of offsetof().)
+   */
   typedef struct qtimer qtimer_t ;
 
   heap_init_new_backlinked(&qtp->timers, 0, (heap_cmp*)qtimer_cmp,
@@ -122,15 +124,18 @@ qtimer_pile_init_new(qtimer_pile qtp)
  * empty, or the top entry times out after the maximum time, then the maximum
  * is returned.
  */
-qtime_mono_t
-qtimer_pile_top_time(qtimer_pile qtp, qtime_mono_t max_time)
+qtime_t
+qtimer_pile_top_wait(qtimer_pile qtp, qtime_t max_wait)
 {
+  qtime_t top_wait ;
   qtimer  qtr = heap_top_item(&qtp->timers) ;
 
-  if ((qtr == NULL) || (qtr->time >= max_time))
-    return max_time ;
-  else
-    return qtr->time ;
+  if (qtr == NULL)
+    return max_wait ;
+
+  top_wait = qtr->time - qt_get_monotonic() ;
+
+  return (top_wait < max_wait) ? top_wait : max_wait ;
 } ;
 
 /* Dispatch the next timer whose time is <= the given "upto" time.
@@ -157,7 +162,6 @@ qtimer_pile_dispatch_next(qtimer_pile qtp, qtime_mono_t upto)
       qtr->state = qtr_state_unset_pending ;
 
       qtr->action(qtr, qtr->timer_info, upto) ;
-      assert(qtp == qtr->pile);
 
       if (qtr->state == qtr_state_unset_pending)
         qtimer_unset(qtr) ;
@@ -372,7 +376,9 @@ qtimer_pile_verify(qtimer_pile qtp)
   vector_index e ;
   qtimer qtr ;
 
-  /* Eclipse flags offsetof(struct qtimer, backlink) as a syntax error :-(  */
+  /* (The typedef is required to stop Eclipse (3.4.2 with CDT 5.0) whining
+   *  about first argument of offsetof().)
+   */
   typedef struct qtimer qtimer_t ;
 
   assert(th->cmp             == (heap_cmp*)qtimer_cmp) ;