[asterisk-dev] [Code Review] 2873: Stasis performance improvements

[David Lee]

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This is an automatically generated e-mail. To reply, visit:
https://reviewboard.asterisk.org/r/2873/
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(Updated Sept. 20, 2013, 4:05 p.m.)


Review request for Asterisk Developers.


Changes
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Review feedback.

* Remove the memsets from internal_ao2_ref entirely, to help malloc_debug find
  fence violations.
* s/i/idx/
* alloc proper size for route tables.
* comments


Repository: Asterisk


Description
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This patch addresses several performance problems that were found in
the initial performance testing of Asterisk 12.

It turns out that we don't have many subscribers to Stasis topics in
the system. We have lots of caching and forwarding, but those don't
use the threadpool. Since we have such a limited number subscribers,
it made sense to simply use taskprocessors and allocate a thread per
subscriber instead.

The Stasis dispatch object was allocated as an AO2 object, even though
it has a very confined lifecycle. This was replaced with a straight
ast_malloc().

The Stasis message router was spending an inordinate amount of time
searching hash tables. In this case, most of our routers had 6 or
fewer routes in them to begin with. This was replaced with an array
that's searched linearly for the route.

We more heavily rely on AO2 objects in Asterisk 12, and the memset()
in ao2_ref() actually became noticeable on the profile. This was
#ifdef'ed to only run when AO2_DEBUG was enabled.

Finally, since we're more reliant on the taskprocessor, it was
optimized to reduce the number of times it was locking/unlocking the
tps mutex.


Diffs (updated)
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  /branches/12/configs/stasis.conf.sample 399546 
  /branches/12/include/asterisk/stasis.h 399546 
  /branches/12/main/astobj2.c 399546 
  /branches/12/main/stasis.c 399546 
  /branches/12/main/stasis_config.c 399546 
  /branches/12/main/stasis_message_router.c 399546 
  /branches/12/main/taskprocessor.c 399546 
  /branches/12/res/res_pjsip/include/res_pjsip_private.h 399546 

Diff: https://reviewboard.asterisk.org/r/2873/diff/


Testing
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Using the setup below, sipp was run against the 12 branch both with
and without my changes.

==
[test-server]$ cat extensions.conf 

[performance]
exten => service,1,Answer
exten => service,n,Wait(1)
exten => service,n,Hangup

[test-server]$ cat sip.conf 

[perf](!)
type=peer
qualify=no
disallow=all
allow=g722
allow=ulaw
insecure=invite,port
context=performance

[test-client](perf)
host=test-client

Simple sipp scenario:
[test-client]$ sipp -sn uac -l 100 -r 50 tests-server


Thanks,

David Lee

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