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https://issues.apache.org/jira/browse/FLEX-34759?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14335585#comment-14335585
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shane doolan commented on FLEX-34759:
-------------------------------------
For each add test, the list starts empty, timer starts, then X items are added.
For each remove tests, the list starts with X items, timer starts, then X items
are removed.
I expect the biggest benefits of this patch will be seen in ArrayCollection
population, as internally ArrayCollection is using ArrayList to manage its
source collection.
If an app has a large number of ArrayCollections or a few large
ArrayCollections being returned by a remote procedure (eg/ BlazeDS, LCDS,
GraniteDS, WebOrb, etc) it will likely experience lag during as the result is
de-serialised and the ArrayCollections are initialised. ArrayCollection.addItem
gets called a lot!
For me, this patch has seen de-serialisation times more than halved. I hope
others will see a similar improvements.
> ArrayList/ArrayCollection performance improvements
> --------------------------------------------------
>
> Key: FLEX-34759
> URL: https://issues.apache.org/jira/browse/FLEX-34759
> Project: Apache Flex
> Issue Type: Improvement
> Components: Collections
> Reporter: shane doolan
> Labels: newbie, patch, performance
> Attachments: FLEX-34759.patch, FLEX-34759_v2.patch, ListProfiler.zip
>
>
> Considerable performance gains can be achieved by avoiding the use of array
> splice when adding/removing items from the start or end of the source array
> in ArrayList.
> eg/ in ArrayList.addItemAt, replace this:
> {code}
> source.splice(index, 0, item);
> {code}
> with this:
> {code}
> if (index == length)
> source.push(item);
> else if (index == 0)
> source.unshift(item);
> else
> source.splice(index, 0, item);
> {code}
> ArrayList.addItem is 10x faster when adding non IEventDispatcher's, and 6x
> faster for IEventDispatcher's. There is a small trade-off when performing
> random access add/removes, where the extra logic slightly increases the times
> taken.
> Since ArrayCollection wraps an ArrayList by default and
> ArrayCollection.addItem is used extensively within our apps, this patch has
> provided considerable performance improvements.
> See profiling results below:
> *Original ArrayList, adding/removing 100k ints*
> * addItemAtStart = "2434ms"
> * addItemAtEnd = "2501ms"
> * addItemAtRandom = "3149ms"
> * removeItemAtStart = "3098ms"
> * removeItemAtEnd = "2401ms"
> * removeItemAtRandom = "2606ms"
> *Original ArrayList, adding/removing 100k IEventDispatcher's*
> * addItemAtStart = "2501ms"
> * addItemAtEnd = "2505ms"
> * addItemAtRandom = "3165ms"
> * removeItemAtStart = "3053ms"
> * removeItemAtEnd = "2453ms"
> * removeItemAtRandom = "2709ms"
> *Patched ArrayList, adding/removing 100k ints*
> * addItemAtStart = "226ms"
> * addItemAtEnd = *"213ms"*
> * addItemAtRandom = "3281ms"
> * removeItemAtStart = "803ms"
> * removeItemAtEnd = "219ms"
> * removeItemAtRandom = "2808ms"
> *Patched ArrayList, adding/removing 100k IEventDispatcher's*
> * addItemAtStart = "415ms"
> * addItemAtEnd = *"488ms"*
> * addItemAtRandom = "3662ms"
> * removeItemAtStart = "878ms"
> * removeItemAtEnd = "264ms"
> * removeItemAtRandom = "2949ms"
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