RFR: 8342818: Implement JEP 509: JFR CPU-Time Profiling [v5]

[Markus Grönlund]

On Mon, 26 May 2025 09:02:39 GMT, Markus Grönlund <mgronlun at openjdk.org> wrote:

>> Yes, but it might be an indeterminate time between entering and exiting the native thread state. So I need to walk them in between. Your sampler implementation also walks threads in native state.
>
> That's fine. Its the term "out of safepoint" which is a concept that does not refer to anything concrete.
> 
> "Sampling" is the process of saving and enqueing a JfrSampleRequest.
> 
> "Stackwalking" or "processing of enqueued requests" is another thing. Are you referring to the second here?
> 
> "out of safepoint" does not make any sense.

Walking from an ljf is walking at a safepoint by design. Its just that in this case, you delegate to another thread to do it.

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PR Review Comment: https://git.openjdk.org/jdk/pull/25302#discussion_r2106894866