RFR: 8359110: Log accumulated GC and process CPU time upon VM exit [v10]

[Jonas Norlinder]

On Mon, 30 Jun 2025 14:02:53 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

>> Jonas Norlinder has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 18 commits:
>> 
>>  - Merge branch 'master' of github.com:JonasNorlinder/openjdk_jdk into gc_cpu_time
>>  - Implement CollectedHeap::before_exit() as suggested by @stefank
>>  - Remove incorrect is_gc_operation call after rebase
>>  - More clean up, remove virtual
>>  - Fixes after feedback from @stefank
>>  - Remove extra whitespace
>>  - operation_is_gc -> is_gc_operation per @stefank suggestion
>>  - Only sample if needed
>>  - Remove explicit super call and minor fixes
>>  - Add CPU time tracking for string deduplication to log_gc_vtime
>>  - ... and 8 more: https://git.openjdk.org/jdk/compare/aa191119...0993931f
>
> src/hotspot/share/gc/shared/collectedHeap.cpp line 70:
> 
>> 68: size_t CollectedHeap::_filler_array_max_size = 0;
>> 69: size_t CollectedHeap::_stack_chunk_max_size = 0;
>> 70: jlong  CollectedHeap::_vm_vtime = 0;
> 
> I'm not sure that the `vm` prefix is fitting for this name.

It is the time we spend on doing GC activities inside the VM thread, hence `vm`.

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PR Review Comment: https://git.openjdk.org/jdk/pull/25779#discussion_r2175174704