On Mon, 24 Feb 2020 23:45:03 GMT, Nir Lisker <nlis...@openjdk.org> wrote:
>> https://bugs.openjdk.java.net/browse/JDK-8185886 >> >> Optimisation to ExpressionHelper.Generic class to use Sets rather than >> Arrays to improve listener removal speed. >> >> This was due to the removal of listeners in TableView taking up to 50% of >> CPU time on the JavaFX Application thread when scrolling/adding rows to >> TableViews. >> >> This may alleviate some of the issues seen here: >> >> TableView has a horrific performance with many columns #409 >> https://github.com/javafxports/openjdk-jfx/issues/409#event-2206515033 >> >> JDK-8088394 : Huge memory consumption in TableView with too many columns >> JDK-8166956: JavaFX TreeTableView slow scroll performance >> JDK-8185887: TableRowSkinBase fails to correctly virtualise cells in >> horizontal direction >> >> OpenJFX mailing list thread: TableView slow vertical scrolling with 300+ >> columns >> https://mail.openjdk.java.net/pipermail/openjfx-dev/2020-January/024780.html > > modules/javafx.base/src/main/java/com/sun/javafx/binding/ExpressionHelper.java > line 194: > >> 193: private Map<InvalidationListener, Integer> >> invalidationListeners = new LinkedHashMap<>(); >> 194: private Map<ChangeListener<? super T>, Integer> changeListeners >> = new LinkedHashMap<>(); >> 195: private T currentValue; > > Two comments on this: > > 1. The old implementation initialized these lazily, so we might want to > preserve that behavior. I think it is reasonable since in most cases an > observable won't have both types of listeners attached to it. > 2. Since we're dealing wither performance optimizations here, we should think > about what the `initialCapcity` and `loadFactor` of these maps should be, as > it can greatly increase performance when dealing with a large amount of > entries. Adding to this, we need to ensure that the simple case of a few listeners doesn't suffer memory bloat. It may make sense to initially allocate a Map with a small capacity and load factor, and then reallocate it if someone adds more than a certain number of listeners. ------------- PR: https://git.openjdk.java.net/jfx/pull/108
