RFR: 8282024: add EscapeAnalysis statistics under PrintOptoStatistics [v14]

[Vladimir Kozlov]

On Fri, 20 May 2022 23:34:25 GMT, Xin Liu <xliu at openjdk.org> wrote:

>> aamarsh has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   make count_MemBar static
>
> src/hotspot/share/opto/escape.cpp line 3756:
> 
>> 3754: 
>> 3755: void ConnectionGraph::print_statistics() {
>> 3756:   // EA stats might be slightly off since objects might be double counted due to iterative EA
> 
> I don't understand. your approach almost worked in last revision.  All you need to do is to adjust for the last iteration. 
> 
> This revision drops it. I don't think it would be "slightly" off, even double counted is optimistic.  A java object will be counted repeat if iterEA iterates N times.  My concern is the final statistical counters become incomparable. 
> 
> Why did you drop snapshot approach in https://github.com/openjdk/jdk/pull/8019/commits/0805514aec4c3d0bd5ec935c089e315e4b37c7fa?

@navyxliu, please, explain what do you mean "snapshot approach" and suggest how we should do it.

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PR: https://git.openjdk.java.net/jdk/pull/8019