RFR: 8342818: Implement CPU Time Profiling for JFR

[Markus Grönlund]

On Tue, 29 Oct 2024 10:56:27 GMT, Johannes Bechberger <jbechberger at openjdk.org> wrote:

> Regarding the field `samplingPeriod`: @apangin mentioned in a recent meeting that naming it `cpuTime` and storing the thread's CPU time at the point of sampling would be better, giving us more flexibility. Not only does it convey more information, but it also allows profiler writers to merge adjacent traces if they are similar, making it possible to store the traces in a more compact format without breaking the API.

Counterargument is that this might confuse in that it is not the 'cpuTime' duration of the method represented by the sample, which is something we are looking to introduce with dynamic instrumentation, not sampling.

We want to be clear that this is the samplingTime attributed, not the cpuTime for the sampled method.

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PR Comment: https://git.openjdk.org/jdk/pull/20752#issuecomment-2443925556