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List:       openjdk-serviceability-dev
Subject:    Re: RFR [XS] Subclasses of jdk.jfr.Event loaded from CDS breaks -XX:FlightRecorderOptions=retransfor
From:       Ioi Lam <ioi.lam () oracle ! com>
Date:       2017-10-30 1:41:38
Message-ID: 11afa7a9-9621-a24a-6451-000baf847da6 () oracle ! com
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Hi Jiangli & Sergei,

Thanks for your review. I have updated the code as suggested by Jiangli 
and pushed.

- Ioi


On 10/26/17 6:00 PM, Jiangli Zhou wrote:
> Hi Ioi,
> 
> SystemDictionary::reorder_dictionary_for_sharing() and \
> Dictionary::reorder_dictionary_for_sharing() are only used for CDS code. Could you \
> please add CDS_ONLY() to the function definitions and put the implementation under \
> #if INCLUDE_CDS. 
> Thanks,
> Jiangli
> 
> > On Oct 26, 2017, at 4:26 PM, Ioi Lam <ioi.lam@oracle.com> wrote:
> > 
> > Please review the follow change:
> > 
> > https://bugs.openjdk.java.net/browse/JDK-8190191
> > http://cr.openjdk.java.net/~iklam/jdk10/8190191-jfr-event-retransform-false.v01.open/
> >  
> > Background:
> > 
> > When -XX:FlightRecorderOptions=retransform=false is given in the command-line,
> > subclasses of jdk.jfr.Event are instrumented at load time with information that's
> > specific to the current JVM lifetime. As a result, we cannot perform
> > such instrumentation at CDS dump time.
> > 
> > A more complicated CDS solution would load these classes from the archive,
> > and re-do the runtime instrumentation. However, there are only a very
> > small number of these classes. The performance benefit of archiving them
> > does not justify the extra complication.
> > 
> > Hence, in this fix, we just identify these classes and exclude them
> > from the CDS archive during run time.
> > 
> > (Because JFR is still a closed feature, the test cases are in the closed repo \
> > ...) 
> > Thanks
> > - Ioi
> > 


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