RFR: 8157023: Integrate NMT with JFR [v2]

[Stefan Johansson]

On Mon, 5 Dec 2022 10:38:40 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

> I have a test with 20k threads. On my machine time under ThreadCritical fluctuates between 30 and 70 ms (I measured debug before accidentally, this is for a release VM). When there is high thread activity (e.g. 20k threads joining), time until we get ThreadCritical can be up to 20 seconds.

Yes, looked a bit at the code and having a lot of threads getting created and dying looks problematic. But I assume this would be problematic even without anyone reading the NMT data. A lot of threads being created would still compete for the `ThreadCritical` (when NMT is enabled), right?

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PR: https://git.openjdk.org/jdk/pull/11449