There is a large performance price currently in the CDR engine. We currently
perform two ao2_callback calls on a container that has an entry for every
channel in the system. This is done to create matching pairs between channels
in a bridge.
As such, the portion of the CDR logic that this patch deals with is how we
make pairings when a channel enters a mixing bridge. In general, when a
channel enters such a bridge, we need to do two things:
(1) Figure out if anyone in the bridge can be this channel's Party B.
(2) Make pairings with every other channel in the bridge that is not already
our Party B.
This is a two step process. In the first step, we look through everyone in the
bridge and see if they can be our Party B (single_state_process_bridge_enter).
If they can - yay! We mark our CDR as having gotten a Party B. If not, we keep
searching. If we don't find one, we wait until someone joins who can be our
Party B.
Step 2 is where we changed the logic
(handle_bridge_pairings and bridge_candidate_process). Previously, we would
first find candidates - those channels in the bridge with us - from the
active_cdrs_by_channel container. Because a channel could be a candidate if it
was Party B to an item in the container, the code implemented multiple
ao2_container callbacks to get all the candidates. We also had to store them
in another container with some other meta information. This was rather complex
and costly, particularly if you have 300 Local channels (600 channels!) going
at once.
Luckily, none of it is needed: when a channel enters a bridge (which is when
we're figuring all this stuff out), the bridge snapshot tells us the unique
IDs of everyone already in the bridge. All we need to do is:
For all channels in the bridge:
If the channel is us or our Party B that we got in step 1, skip it
Compare us and the candidate to figure out who is Party A (based on some
specific rules)
If we are Party A:
Make a new CDR for us, append it to our chain, and set the candidate as
Party B
If they are Party A:
If they don't have a Party B:
Make a new CDR for them, append us to their chain, and us as Party B
Otherwise:
Copy us over as Party B on their existing CDR.
This patch does that.
Because we now use channel unique IDs to find the candidates during bridging,
active_cdrs_by_channel now looks up things using uniqueid instead of channel
name. This makes the more complex code simpler; it does, however, have the
drawback that dialplan applications and functions will be slightly slower as
they have to iterate through the container looking for the CDR by name.
That's a small price to pay however as the bridging code will be called a lot
more often.
This patch also does two other minor changes:
(1) It reduces the container size of the channels in a bridge snapshot to 1.
In order to be predictable for multi-party bridges, the order of the
channels in the container must be stable; that is, it must always devolve
to a linked list.
(2) CDRs and the multi-party test was updated to show the relationship between
two dialed channels. You still want to know if they talked - previously,
dialed channels were always ignored, which is wrong when they have
managed to get a Party B.
(closes issue ASTERISK-22488)
Reported by: Richard Mudgett
Review: https://reviewboard.asterisk.org/r/2861/
........
Merged revisions 399666 from http://svn.asterisk.org/svn/asterisk/branches/12
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@399667 65c4cc65-6c06-0410-ace0-fbb531ad65f3
........
r397921 | mmichelson | 2013-08-29 10:42:10 -0500 (Thu, 29 Aug 2013) | 6 lines
Resolve assumptions that bridge snapshots would be non-NULL for transfer stasis events.
Attempting to transfer an unbridged call would result in crashes in either CEL code or
in the conversion to AMI messages.
........
r397922 | mmichelson | 2013-08-29 10:42:29 -0500 (Thu, 29 Aug 2013) | 3 lines
Remove extra debug message.
........
Merged revisions 397921-397922 from http://svn.asterisk.org/svn/asterisk/branches/12
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@397923 65c4cc65-6c06-0410-ace0-fbb531ad65f3
Stasis events (which get distributed over the ARI WebSocket) are created
by subscribing to the channel_all_cached and bridge_all_cached topics,
filtering out events for channels/bridges currently subscribed to.
There are two issues with that. First was a race condition, where
messages in-flight to the master subscribe-to-all-things topic would get
sent out, even though the events happened before the channel was put
into Stasis. Secondly, as the number of channels and bridges grow in the
system, the work spent filtering messages becomes excessive.
Since r395954, individual channels and bridges have caching topics, and
can be subscribed to individually. This patch takes advantage, so that
channels and bridges are subscribed to on demand, instead of filtering
the global topics.
The one case where filtering is still required is handling BridgeMerge
messages, which are published directly to the bridge_all topic.
Other than the change to how subscriptions work, this patch mostly just
moves code around. Most of the work generating JSON objects from
messages was moved to .to_json handlers on the message types. The
callback functions handling app subscriptions were moved from res_stasis
(b/c they were global to the model) to stasis/app.c (b/c they are local
to the app now).
(closes issue ASTERISK-21969)
Reported by: Matt Jordan
Review: https://reviewboard.asterisk.org/r/2754/
........
Merged revisions 397816 from http://svn.asterisk.org/svn/asterisk/branches/12
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@397820 65c4cc65-6c06-0410-ace0-fbb531ad65f3
* Changed ast_manager_build_bridge_state_string() to assume an empty
prefix string just like ast_manager_build_channel_state_string().
* Created ast_manager_build_bridge_state_string_prefix() to work just like
ast_manager_build_channel_state_string_prefix().
* Made BridgeMerge AMI event use To/From prefixes.
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@396417 65c4cc65-6c06-0410-ace0-fbb531ad65f3
* BridgeEnter now contains the unique ID of the channel that is to be swapped out, if applicable.
* There is a ParkedCallSwap event that is sent when a parked channel has a new channel take its place.
(closes issue ASTERISK-22193)
reported by Mark Michelson
Review: https://reviewboard.asterisk.org/r/2712
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@396107 65c4cc65-6c06-0410-ace0-fbb531ad65f3
This prevents XML documentation duplication by expanding channel and
bridge snapshot tags into channel and bridge snapshot parameter sets
with a given prefix or defaulting to no prefix. This also prevents
documentation from becoming fractured and out of date by keeping all
variations of the documentation in template form such that it only
needs to be updated once and keeps maintenance to a minimum.
Review: https://reviewboard.asterisk.org/r/2708/
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@395985 65c4cc65-6c06-0410-ace0-fbb531ad65f3
In working with res_stasis, I discovered a significant limitation to
the current structure of stasis_caching_topics: you cannot subscribe
to cache updates for a single channel/bridge/endpoint/etc.
To address this, this patch splits the cache away from the
stasis_caching_topic, making it a first class object. The stasis_cache
object is shared amongst individual stasis_caching_topics that are
created per channel/endpoint/etc. These are still forwarded to global
whatever_all_cached topics, so their use from most of the code does
not change.
In making these changes, I noticed that we frequently used a similar
pattern for bridges, endpoints and channels:
single_topic ----------------> all_topic
^
|
single_topic_cached ----+----> all_topic_cached
|
+----> cache
This pattern was extracted as the 'Stasis Caching Pattern', defined in
stasis_caching_pattern.h. This avoids a lot of duplicate code between
the different domain objects.
Since the cache is now disassociated from its upstream caching topics,
this also necessitated a change to how the 'guaranteed' flag worked
for retrieving from a cache. The code for handling the caching
guarantee was extracted into a 'stasis_topic_wait' function, which
works for any stasis_topic.
(closes issue ASTERISK-22002)
Review: https://reviewboard.asterisk.org/r/2672/
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@395954 65c4cc65-6c06-0410-ace0-fbb531ad65f3
This patch renames the bridging* files to bridge*. This may seem pedantic
and silly, but it fits better in line with current Asterisk naming conventions:
* channel is not "channeling"
* monitor is not "monitoring"
etc.
A bridge is an object. It is a first class citizen in Asterisk. "Bridging" is
the act of using a bridge on a set of channels - and the API that fulfills that
role is more than just the action.
(closes issue ASTERISK-22130)
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@395378 65c4cc65-6c06-0410-ace0-fbb531ad65f3