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From "Alex Harui (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (FLEX-34759) ArrayList/ArrayCollection performance improvements
Date Tue, 24 Feb 2015 09:46:04 GMT

    [ https://issues.apache.org/jira/browse/FLEX-34759?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14334724#comment-14334724
] 

Alex Harui commented on FLEX-34759:
-----------------------------------

That's great!  Good to know that it was mostly debug info causing the slow down.

You are correct that you can't trust small samples that run in a few milliseconds.  IMO, the
patch is good enough.  Maybe Piotr will find time to finish committing your updated version.

I don't see anything in the patch that should be size dependent.  In your actual test case,
is the list really 100K in size or are you executing 100K adds on some smaller list because
there are removeItems going on as well.  I would imagine anyone shoving a lot of new transactions
into the front of a list and kicking out old things will be glad to see this optimization.

Thanks for contributing.

> 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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