RFR: 8310994: Add JFR event for selection operations [v3]

[Tim Prinzing]

On Thu, 11 Apr 2024 16:39:24 GMT, Daniel Fuchs <dfuchs at openjdk.org> wrote:

>> I think it's okay for now. If there is another phase of this work to help diagnose spinning issues then it will need to re-visited. I'm very concerned about the possible changes for that second phase, but this first phase of instrumentation is not disruptive.
>
> OK. I am a little concerned about how often this event will be fired when using the HttpClient - given that it's enabled by default. Idle connections sitting in the pool will fire it at least once per connection every 1500ms. That may not be too bad.

Should I set the default to be fairly high (like maybe 1600ms)?  I think to be useful people will have to set the threshold to something that fits their needs anyway.

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PR Review Comment: https://git.openjdk.org/jdk/pull/16710#discussion_r1583825215