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List:       openjdk-serviceability-dev
Subject:    RFR: JDK-8215624 add parallel heap inspection support for jmap histo(G1)(Internet mail)
From:       linzang(臧琳) <linzang () tencent ! com>
Date:       2020-02-19 1:40:34
Message-ID: c75874892032465b90fbd03ad29242d2 () tencent ! com
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Re-post this RFR with correct enhancement number to make it trackable.
please ignore the previous wrong post. sorry for troubles. 

webrev: http://cr.openjdk.java.net/~lzang/jmap-8214535/8215624/webrev_01/
bug: https://bugs.openjdk.java.net/browse/JDK-8215624
CSR: https://bugs.openjdk.java.net/browse/JDK-8239290
--------------
Lin
> Hi Lin,
> 
> Could you, please, re-post your RFR with the right enhancement number in
> the message subject?
> It will be more trackable this way.
> 
> Thanks,
> Serguei
> 
> 
> On 2/17/20 10:29 PM, linzang(臧琳) wrote:
> > Dear David,
> > Thanks a lot!
> > I have updated the refined code to \
> > http://cr.openjdk.java.net/~lzang/jmap-8214535/8215264/webrev_01/. IMHO the \
> > parallel heap inspection can be extended to all kinds of heap as long as the heap \
> > layout can support parallel iteration. Maybe we can firstly use this webrev to \
> > discuss how to implement it, because I am not sure my current implementation is \
> > an appropriate way to communicate with collectedHeap, then we can extend the \
> > solution to other kinds of heap. 
> > Thanks,
> > --------------
> > Lin
> > > Hi Lin,
> > > 
> > > Adding in hotspot-gc-dev as they need to see how this interacts with GC
> > > worker threads, and whether it needs to be extended beyond G1.
> > > 
> > > I happened to spot one nit when browsing:
> > > 
> > > src/hotspot/share/gc/shared/collectedHeap.hpp
> > > 
> > > +   virtual bool run_par_heap_inspect_task(KlassInfoTable* cit,
> > > +                                          BoolObjectClosure* filter,
> > > +                                          size_t* missed_count,
> > > +                                          size_t thread_num) {
> > > +     return NULL;
> > > 
> > > s/NULL/false/
> > > 
> > > Cheers,
> > > David
> > > 
> > > On 18/02/2020 2:15 pm, linzang(臧琳) wrote:
> > > > Dear All,
> > > > May I ask your help to review the follow changes:
> > > > webrev:
> > > > http://cr.openjdk.java.net/~lzang/jmap-8214535/8215264/webrev_00/
> > > > bug: https://bugs.openjdk.java.net/browse/JDK-8215624
> > > > related CSR: https://bugs.openjdk.java.net/browse/JDK-8239290
> > > > This patch enable parallel heap inspection of G1 for jmap histo.
> > > > my simple test shown it can speed up 2x of jmap -histo with
> > > > parallelThreadNum set to 2 for heap at ~500M on 4-core platform.
> > > > 
> > > > ------------------------------------------------------------------------
> > > > BRs,
> > > > Lin
> > > 
> 


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