RFR: 8246745: ListCell/Skin: misbehavior on switching skin

Jeanette Winzenburg fastegal at openjdk.java.net
Mon Jun 15 09:56:17 UTC 2020

On Mon, 15 Jun 2020 09:44:40 GMT, Ambarish Rapte <arapte at openjdk.org> wrote:

>> a bit less flippant: really interested in the measurements - certainly, they are somewhere but can't find anything. Any
>> pointer where to look?
> Even I do not know if there are any performance measurements for such scenario. :) May be @kevinrushforth could help in
> that.  I just counted the calls by adding a log, and observed that for a ListView with only one item, these three
> methods combinely are called 23 times when the Stage is displayed for the first time and 5 times when the item is
> selected. (updated the counts after rechecking, looks like the methods are invoked for empty cells too, which seems
> correct)

hmm, do you mean a list with height of one cell only?

My experiment (having counters per instance and per computeXXHeight), logs 1 (or 2) for computePref with fixed size and
5 (1 each for min/max and 3 for pref) without fixedSize per layout pass. So it's 5* access of either the local field or
the listView method .. wouldn't expect any problems, but then assumed performance is reading in coffee ground :)

Let's hope there are some metrics to use :)


PR: https://git.openjdk.java.net/jfx/pull/251

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