RFR: 8307346 - Add missing gc+phases logging for ObjectCount(AfterGC) JFR event collection code [v2]

[Aleksey Shipilev]

On Wed, 3 May 2023 10:40:24 GMT, olivergillespie <duke at openjdk.org> wrote:

>> Add logging for the time taken to collect/report ObjectCount(AfterGC) event to Serial, Parallel and G1 full collectors, for parity with the G1 concurrent collector. This event can be *very* expensive to collect (single threaded STW full heap scan), so it's very important to show it clearly to the user.
>> 
>> Added output:
>> 
>> Serial
>> 
>> [7.976s][debug][gc,phases      ] GC(7) Trigger cleanups 0.002ms
>> [7.977s][debug][gc,phases      ] GC(7) Class Unloading 0.556ms
>> ++ [7.977s][debug][gc,phases,start] GC(7) Report Object Count
>> ++ [8.529s][debug][gc,phases      ] GC(7) Report Object Count 552.065ms
>> [8.529s][info ][gc,phases      ] GC(7) Phase 1: Mark live objects 1066.882ms
>> [8.529s][info ][gc,phases,start] GC(7) Phase 2: Compute new object addresses
>> 
>> Parallel
>> 
>> [5.786s][debug][gc,phases      ] GC(12) Trigger cleanups 0.002ms
>> [5.786s][debug][gc,phases      ] GC(12) Class Unloading 0.556ms
>> ++ [5.786s][debug][gc,phases,start] GC(12) Report Object Count
>> ++ [6.313s][debug][gc,phases      ] GC(12) Report Object Count 526.307ms
>> [6.313s][info ][gc,phases      ] GC(12) Marking Phase 889.900ms
>> [6.313s][info ][gc,phases,start] GC(12) Summary Phase
>> 
>> G1 Full
>> 
>> [3.922s][debug][gc,phases         ] GC(24) Trigger cleanups 0.002ms
>> [3.922s][debug][gc,phases         ] GC(24) Phase 1: Class Unloading and Cleanup 0.159ms
>> ++ [3.922s][debug][gc,phases,start   ] GC(24) Report Object Count
>> ++ [4.442s][debug][gc,phases         ] GC(24) Report Object Count 519.292ms
>> [4.442s][info ][gc,phases         ] GC(24) Phase 1: Mark live objects 653.209ms
>> [4.442s][info ][gc,phases,start   ] GC(24) Phase 2: Prepare compaction
>
> olivergillespie has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Use correct holder var names

This looks fine to me.

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Marked as reviewed by shade (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/13772#pullrequestreview-1410628693