RFR (S) 8073705: more performance issues in class redefinition

Coleen Phillimore coleen.phillimore at oracle.com
Mon Apr 27 17:49:56 UTC 2015


This looks nice.  I thought this change was going to delay calling 
AdjustCpoolCacheAndVtable until the end of the redefinition, rather than 
for each class, so was a bit confused by the change.

Your change is a nice cleanup and improves MethodHandle method 
replacement performance.

Your backport may not be simple for jdk8 because PreviousVersionNode is 
another type and not an InstanceKlass.  Maybe you've convinced me that 
it's worth backporting those changes too.  Let me know.


On 4/10/15, 4:29 PM, serguei.spitsyn at oracle.com wrote:
> Hi Coleen and Dan,
> This is the second class redefinition scalability/optimization fix 
> that is in my queue to push into 9 and 8u60.
> The approach is similar to the first one but much smaller.
> For convenience, these are the links to the first scalability fix:
>      Bug report: https://bugs.openjdk.java.net/browse/JDK-8073705
>      Open webrev: 
> http://cr.openjdk.java.net/~sspitsyn/webrevs/2015/hotspot/8046246-JVMTI-redefscale.2/
> Please, let me know if you have any chance to review this.
> This is the last one that is waiting for your attention! :)
> Thanks,
> Serguei
> On 3/26/15 7:38 PM, serguei.spitsyn at oracle.com wrote:
>> Please, review the fix for:
>>   https://bugs.openjdk.java.net/browse/JDK-8073705
>> Open hotspot webrev:
>> http://cr.openjdk.java.net/~sspitsyn/webrevs/2015/hotspot/8073705-JVMTI-redefscale2.1/ 
>> Summary:
>>    This is the 2-nd round of performance/calability fixes in class 
>> redefinition.
>>    This time, the two remaining issues that were left alone in the 
>> first round fix:
>>      - optimized ConstantPoolCache::adjust_method_entries() is used 
>> for previous versions
>>      - the MemberNameTable::adjust_method_entries() has been 
>> optimized too
>>      - some cleanup
>> Testing:
>>   In progress: nsk redefine classes tests, JTREG 
>> java/lang/instrument, com/sun/jdi
>> Thanks,
>> Serguei

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