[jira] [Commented] (ARTEMIS-3848) High cpu usage on ReadWrite locks

["Clebert Suconic (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/ARTEMIS-3848?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17542047#comment-17542047 ] 

Clebert Suconic commented on ARTEMIS-3848:
------------------------------------------

we should ban any non static Threadlocal from our codebase.

> High cpu usage on ReadWrite locks
> ---------------------------------
>
>                 Key: ARTEMIS-3848
>                 URL: https://issues.apache.org/jira/browse/ARTEMIS-3848
>             Project: ActiveMQ Artemis
>          Issue Type: Bug
>    Affects Versions: 2.22.0
>            Reporter: Clebert Suconic
>            Assignee: Clebert Suconic
>            Priority: Major
>             Fix For: 2.23.0
>
>
> our HandlerBase is setting a boolean value if it's in handler.
> I thought by setting it to null I was clearing the ThreadLocal variable, however that's just creating a null entry.
> What makes it worst is the fact that threadLocal was non static. as a result we are getting a lot of entries on the ThreadLocal HashMap. as connections come and go, that will generate a leak on the thread.
> That will cause threads on the following stack trace to consume a lot of CPU:
>         at java.lang.ThreadLocal$ThreadLocalMap.expungeStaleEntry(ThreadLocal.java:638)
>         at java.lang.ThreadLocal$ThreadLocalMap.remove(ThreadLocal.java:520)
>         at java.lang.ThreadLocal$ThreadLocalMap.access$200(ThreadLocal.java:319)
>         at java.lang.ThreadLocal.remove(ThreadLocal.java:242)
>         at java.util.concurrent.locks.ReentrantReadWriteLock$Sync.tryReleaseShared(ReentrantReadWriteLock.java:426)
>         at java.util.concurrent.locks.AbstractQueuedSynchronizer.releaseShared(AbstractQueuedSynchronizer.java:1341)
>         at java.util.concurrent.locks.ReentrantReadWriteLock$ReadLock.unlock(ReentrantReadWriteLock.java:881)



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