RFR: 8252936: Optimize removal of listeners from ExpressionHelper.Generic

[Kevin Rushforth]

On Wed, 26 Aug 2020 14:08:37 GMT, dannygonzalez <github.com+6702882+dannygonzalez at openjdk.org> wrote:

>> @hjohn, agreed regards the issues of adding a listener to each node.
>> 
>> Would it be worth doing the additional work of updating PopupWindow and ProgressIndicatorSkin to add their own listeners to make this a pull request that can be reviewed officially?
>> 
>> I await any further comments from @kevinrushforth et al.
>
> I have attached a code sample. If you use OpenJFX 16-ea+1 and run visual VM and look at the hotspots in the JavaFX thread, you can see that about 45% of the time in the JavaFX thread is spent in removeListener calls.
> 
> Note: In CPU settings of VisualVM, I removed all packages from the "Do not profile packages section".
> 
> [JavaFXSluggish.java.zip](https://github.com/openjdk/jfx/files/5130298/JavaFXSluggish.java.zip)

@dannygonzalez Per [this message](https://mail.openjdk.java.net/pipermail/openjfx-dev/2020-September/027534.html) on the openjfx-dev mailing list, I have filed a new JBS issue for this PR to use. Please change the title to:

8252936: Optimize removal of listeners from ExpressionHelper.Generic

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PR: https://git.openjdk.java.net/jfx/pull/108