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

serguei.spitsyn at oracle.com serguei.spitsyn at oracle.com
Tue Apr 28 04:27:46 UTC 2015

On 4/27/15 1:25 PM, serguei.spitsyn at oracle.com wrote:

On 4/27/15 1:05 PM, serguei.spitsyn at oracle.com wrote:

Hi Coleen,

Thank you for the review! On 4/27/15 10:49 AM, Coleen Phillimore wrote:

Serguei, 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. I consider this for as a next round of optimizations which is more risky. We need to decide when we are Ok to take this risk. My guess is that it is better to do it together with the constant pool merge elimination. Sorry, I forgot to tell that my plan is to open another bug that should cover moving all this adjustments to the end of redefinition. This was a source of the confusion!

I've filed a separate bug report for the above: https://bugs.openjdk.java.net/browse/JDK-8078725

Thanks, Serguei

Thanks, Serguei

Your change is a nice cleanup and improves MethodHandle method replacement performance. Thanks! 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. I've already backported the first chunk where this problem was hit. It seems, this one should not be harder to backport. Thanks! Serguei Thanks, Coleen 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::adjustmethodentries() is used for previous versions - the MemberNameTable::adjustmethodentries() 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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