Merged revisions 184339 via svnmerge from

https://origsvn.digium.com/svn/asterisk/trunk

........
r184339 | russell | 2009-03-25 16:57:19 -0500 (Wed, 25 Mar 2009) | 35 lines

Improve performance of the ast_event cache functionality.

This code comes from svn/asterisk/team/russell/event_performance/.

Here is a summary of the changes that have been made, in order of both
invasiveness and performance impact, from smallest to largest.

1) Asterisk 1.6.1 introduces some additional logic to be able to handle
   distributed device state.  This functionality comes at a cost.
   One relatively minor change in this patch is that the extra processing
   required for distributed device state is now completely bypassed if
   it's not needed.

2) One of the things that I noticed when profiling this code was that a
   _lot_ of time was spent doing string comparisons.  I changed the way
   strings are represented in an event to include a hash value at the front.
   So, before doing a string comparison, we do an integer comparison on the
   hash.

3) Finally, the code that handles the event cache has been re-written.
   I tried to do this in a such a way that it had minimal impact on the API.
   I did have to change one API call, though - ast_event_queue_and_cache().
   However, the way it works now is nicer, IMO.  Each type of event that
   can be cached (MWI, device state) has its own hash table and rules for
   hashing and comparing objects.  This by far made the biggest impact on
   performance.

For additional details regarding this code and how it was tested, please see the
review request.

(closes issue #14738)
Reported by: russell

Review: http://reviewboard.digium.com/r/205/

........


git-svn-id: http://svn.digium.com/svn/asterisk/branches/1.6.1@184342 f38db490-d61c-443f-a65b-d21fe96a405b

1 files changed, 16 insertions, 32 deletions

diff --git a/res/ais/evt.c b/res/ais/evt.c
index 0057f0481..7e8c8adf6 100644
--- a/res/ais/evt.c
+++ b/res/ais/evt.c
@@ -47,6 +47,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$");
 #include "asterisk/event.h"
 #include "asterisk/config.h"
 #include "asterisk/linkedlists.h"
+#include "asterisk/devicestate.h"
 
 #ifndef AST_MODULE
 /* XXX HACK */
@@ -111,34 +112,7 @@ void evt_channel_open_cb(SaInvocationT invocation, SaEvtChannelHandleT channel_h
 
 static void queue_event(struct ast_event *ast_event)
 {
-	enum ast_event_type type;
-
-	/*! 
-	 * \todo This hack macks me sad.  I need to come up with a better way to
-	 *       figure out whether an event should be cached or not, and what
-	 *       parameters to cache on.
-	 *
-	 *       As long as the types of events that are supported is limited,
-	 *       this isn't *terrible*, I guess.  Perhaps we should just define
-	 *       caching rules in the core, and make them configurable, and not
-	 *       have it be the job of the event publishers.
-	 */
-
-	type = ast_event_get_type(ast_event);
-
-	if (type == AST_EVENT_MWI) {
-		ast_event_queue_and_cache(ast_event,
-			AST_EVENT_IE_MAILBOX, AST_EVENT_IE_PLTYPE_STR,
-			AST_EVENT_IE_CONTEXT, AST_EVENT_IE_PLTYPE_STR,
-			AST_EVENT_IE_END);
-	} else if (type == AST_EVENT_DEVICE_STATE_CHANGE) {
-		ast_event_queue_and_cache(ast_event,
-			AST_EVENT_IE_DEVICE, AST_EVENT_IE_PLTYPE_STR,
-			AST_EVENT_IE_EID, AST_EVENT_IE_PLTYPE_RAW, sizeof(struct ast_eid),
-			AST_EVENT_IE_END);
-	} else {
-		ast_event_queue(ast_event);
-	}
+	ast_event_queue_and_cache(ast_event);
 }
 
 void evt_event_deliver_cb(SaEvtSubscriptionIdT sub_id,
@@ -341,9 +315,14 @@ static void add_publish_event(struct event_channel *event_channel, const char *e
 		return;
 	}
 
-	if (!(publish_event = ast_calloc(1, sizeof(*publish_event))))
+	if (type == AST_EVENT_DEVICE_STATE_CHANGE && ast_enable_distributed_devstate()) {
 		return;
-	
+	}
+
+	if (!(publish_event = ast_calloc(1, sizeof(*publish_event)))) {
+		return;
+	}
+
 	publish_event->type = type;
 	ast_log(LOG_DEBUG, "Subscribing to event type %d\n", type);
 	publish_event->sub = ast_event_subscribe(type, ast_event_cb, event_channel,
@@ -399,9 +378,14 @@ static void add_subscribe_event(struct event_channel *event_channel, const char
 		return;
 	}
 
-	if (!(subscribe_event = ast_calloc(1, sizeof(*subscribe_event))))
+	if (type == AST_EVENT_DEVICE_STATE_CHANGE && ast_enable_distributed_devstate()) {
 		return;
-	
+	}
+
+	if (!(subscribe_event = ast_calloc(1, sizeof(*subscribe_event)))) {
+		return;
+	}
+
 	subscribe_event->type = type;
 	subscribe_event->id = ast_atomic_fetchadd_int(&unique_id, +1);