RFR: 8352251: Implement Cooperative JFR Sampling [v14]

[Martin Doerr]

On Wed, 30 Apr 2025 13:50:53 GMT, Martin Doerr <mdoerr at openjdk.org> wrote:

> Can we let _last_sender_Java_fp be a state field that can be tested?

I still couldn't hit any failures or errors with my simple version, but I understand that it might be problematic.

I have an implementation: https://github.com/TheRealMDoerr/jdk/commit/b2f83fae262f129f864e109d7adce169e28f0c7c
Please take a look. I hope we don't need more ;-)
I'm planning to run more test when I find more time.

If `_last_sender_Java_fp` is needed on all platforms, shouldn't it be better moved to shared javaFrameAnchor.hpp and javaThread.hpp?

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PR Comment: https://git.openjdk.org/jdk/pull/24296#issuecomment-2851350228