[logback-dev] [JIRA] Closed: (LBCLASSIC-153) Excessive synchronization in ReconfigureOnChangeFilter.decide

[Ceki Gulcu (JIRA)]

     [ http://jira.qos.ch/browse/LBCLASSIC-153?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Ceki Gulcu closed LBCLASSIC-153.
--------------------------------

    Resolution: Cannot Reproduce

Hello,

I have tried to reproduce this bug by creating a relevant test case, called ReconfigurePerf, part of the  ch.qos.logback.classic.turbo package (in src/test) and measuring its performance on 4 core CPU with 5 threads. JProfiler showed that only a marginal percentage of CPU was spent in ReconfigureOnChangeFilter's decide method. Using Yourkit yielded similar results. 

So, either

1) ReconfigurePerf is non-representative
2) I misused the profiler
3) your tests are non-representative

In the mean-time I am marking this bug as "Cannot reproduce". If after profiling ReconfigurePerf you obtain a different result, or you detect an error in the test, do not hesitate to reopen this report.

> Excessive synchronization in ReconfigureOnChangeFilter.decide
> -------------------------------------------------------------
>
>                 Key: LBCLASSIC-153
>                 URL: http://jira.qos.ch/browse/LBCLASSIC-153
>             Project: logback-classic
>          Issue Type: Bug
>    Affects Versions: 0.917
>            Reporter: Anders Wallgren
>            Assignee: Ceki Gulcu
>         Attachments: screenshot-1.jpg
>
>
> The synchronization in ReconfigureOnChangeFilter.decide hurts scalability.
> It seems unnecessary to serialize the code in changeDetected -- it should be possible to use atomic updates of nextCheck and lastModified and only serialize the actual reconfiguration.

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