RFR: 8037914: Add JFR event for string deduplication

Tue Oct 28 23:57:02 UTC 2025

On Tue, 28 Oct 2025 23:36:23 GMT, Erik Gahlin <egahlin at openjdk.org> wrote:

> > I don't, I created two events just to separate information in two uniform containers. Potentially, users may want to enable just one of them.
> 
> Roughly how many events can we expect per second? One, one hundred or ten thousand?

It depends on the allocation pattern, but in principle string deduplication is triggered at the end of a young GC. So the number of events per second should be roughly the same order of magnitude.

There's a ticket about repeated consecutive deduplication rounds which are not related to a completed GC cycle: [JDK-8315238](https://bugs.openjdk.org/browse/JDK-8315238)
I guess the event in this PR will suffer from the same potential behavior, but the numbers do not seem particularly concerning to me.

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PR Comment: https://git.openjdk.org/jdk/pull/28015#issuecomment-3459044169