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https://issues.apache.org/jira/browse/AMQ-3454?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13410277#comment-13410277
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Yves Rey commented on AMQ-3454:
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Hi Gary,
Yes, I saw your changes and I agree they will significantly reduce the
contention on the mutex, but there is still a copy made in
RegionBroker#getDestinationMap. That copy is now out of the mutex thus will not
trigger contention, but is still much heavier than doing a hash lookup.
Also, since you are returning a reference of the map, I believe the read lock
in getDestinationMap is likely useless. And I wonder that even if it is not the
case currently, some code could modify the content of the returned map outside
the mutex mechanism that guarantees integrity of the list of destinations.
Yves.
> Contention on a mutex during a stress when using SimpleAuthenticationPlugin
> ---------------------------------------------------------------------------
>
> Key: AMQ-3454
> URL: https://issues.apache.org/jira/browse/AMQ-3454
> Project: ActiveMQ
> Issue Type: Bug
> Components: Broker
> Affects Versions: 5.5.0
> Reporter: William
> Assignee: Gary Tully
> Priority: Critical
> Fix For: 5.6.0
>
> Attachments: RWLockDestinations.txt, amq-config.zip, amq-dump
>
>
> I am testing ActiveMQ 5.5 with my own stress test. I tried to implement a
> stress test that use jms ressource in the same fashion that my application
> would do.
> For that, I used jms template (from Spring) and a pooled connection factory
> (as recommended). I run a fixed number of thread that plublish on fixed
> number of topics. Each thread pick up a topic and enter a loop that will send
> a message on the choosen topic.
> The issue is reproductible with SimpleAuthenticationPlugin active.
> Configuration of the test :
> * 100 topics
> * more than one thread per topic (actually 1500 producer threads)
> Common connection properties :
> * alwaysSessionAsync=false
> * dispatchAsync=false
> * optimizeAcknowledge=true
> *
> socketBufferSize=131072&trace=true&wireFormat.cacheSize=2048&wireFormat.tcpNoDelayEnabled=true&wireFormat.tightEncodingEnabled=true&keepAlive=true&soTimeout=10000&connectionTimeout=10000\
> Producers :
> * Message are not persistent
> * There is no transaction
> * Message expiration time is 30s
> * Unsing JMS template singleton with a PooledConnectionFactory
> * 3 JVM running
> * connection options alwaysSyncSend=true,copyMessageOnSend=false
> Consumers :
> * just listening to each topic with a SimpleMessageListenerContainer and
> count messages received
> * 3 JVM running
> In attachment, you will find activemq config file and thread dumps. I can
> attach the producer/consumers code if you need it but I think you have your
> own tests.
> This Jira is critical for me because security is mandatory for our use.
> If you need more information, please ask.
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