RFR: 8310994: Add JFR event for selection operations [v2]

[Tim Prinzing]

On Thu, 23 Nov 2023 11:18:45 GMT, Erik Gahlin <egahlin at openjdk.org> wrote:

>> src/jdk.jfr/share/classes/jdk/jfr/events/SelectionEvent.java line 43:
>> 
>>> 41: 
>>> 42:     @Label("Selection Count")
>>> 43:     @Description("Number of channels selected")
>> 
>> I suspect you'll need to rename this event to something like "SelectorSelect" as "Selection" could be anything.
>> 
>> We'll to find a better name for the field and the label too. There are two forms of selection operations. One form operates on a selected-key set where the select/selectNow methods returns the number of keys aded to the Selector's ready set. The other form performs an action on each selected key. I'll try to come up a suggestions for the names, I suspect a label "number of channels ready for I/O or added to ready set" would be the most accurate.
>
> It would also be good if the name reflect that it is related to channels so it won't clash with other events in the future.

I've made the suggested changes.  I changed the "count" field to "selectorKeyCount" which hopefully seems reasonable.

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PR Review Comment: https://git.openjdk.org/jdk/pull/16710#discussion_r1425746321