From 9856e17cf2495d1f7db16e866f16bc4a8447524d Mon Sep 17 00:00:00 2001
From: Chris Hall <GMCH@hestia.halldom.com>
Date: Tue, 16 Feb 2010 09:52:14 +0000
Subject: 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
---
 lib/mqueue.h | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

(limited to 'lib/mqueue.h')

diff --git a/lib/mqueue.h b/lib/mqueue.h
index d8790246..355aec23 100644
--- a/lib/mqueue.h
+++ b/lib/mqueue.h
@@ -93,16 +93,16 @@ typedef void mqueue_action(mqueue_block mqb, mqb_flag_t flag) ;
 enum { mqb_args_size_max  = 64 } ;      /* maximum size of struct args  */
 enum { mqb_argv_size_unit = 16 } ;      /* allocate argv in these units */
 
-struct args
+struct mqb_args
 {
-  char data[mqb_args_size_max] ;        /* empty space                  */
+  char bytes[mqb_args_size_max] ;       /* empty space                  */
 } ;
 
 #define MQB_ARGS_SIZE_OK(s) CONFIRM(sizeof(struct s) <= mqb_args_size_max)
 
 struct mqueue_block
 {
-  struct args     args ;                /* user structure               */
+  struct mqb_args args ;                /* user structure               */
 
   mqueue_block    next ;                /* single linked list           */
 
@@ -116,8 +116,12 @@ struct mqueue_block
   mqb_index_t argv_next ;               /* iterator                     */
 } ;
 
-/* mqueue_block structures are malloced.  That guarantees maximum alignment.  */
-/* To guarantee maximum alignment for "struct args", it must be first item !  */
+/* mqueue_block structures are malloced.  That guarantees maximum alignment.
+ * To guarantee maximum alignment for "struct args", it must be first item !
+ *
+ * (The typedef is required to stop Eclipse (3.4.2 with CDT 5.0) whining
+ *  about first argument of offsetof().)
+ */
 typedef struct mqueue_block mqueue_block_t ;
 CONFIRM(offsetof(mqueue_block_t, args) == 0) ;
 
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