Problem with "new Group()" performance

Question

Hello
I need to create many spark.components.Group objects (more than 10000) and have some performance problem. In many cases new object was created in 0-5 ms, but sometimes in 266-700 ms.
This is output from my test app (code below):
[Time] - [Count]
0 - 91035
1 - 7308
2 - 393
3 - 365
4 - 408
5 - 404
6 - 66
7 - 3
8 - 3
9 - 2
10 - 1
12 - 1
13 - 1
16 - 1
19 - 1
24 - 1
39 - 1
63 - 1
67 - 1
210 - 1
260 - 1
266 - 1
690 - 1
And code:
<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/halo" minWidth="1024" minHeight="768" applicationComplete="windowedapplication1_applicationCompleteHandler(event)">
    <fx:Script>
    <![CDATA[
        import mx.events.FlexEvent;
        import spark.components.Group;
        private var container:Array = new Array();
        protected function windowedapplication1_applicationCompleteHandler(event:FlexEvent):void {
            var map:Object = new Object();
            var i:int, start:int, stop:int;
            var grp:Group;
            for(i = 0; i != 100000; i++) {
                start = new Date().getTime();
                grp = new Group();
                stop = new Date().getTime();
                if (!map.hasOwnProperty(stop - start)) {
                    map[stop - start] = 0;
                map[stop - start]++;
                container.push(grp);
            for (var key:* in map) {
                trace(key + " - " + map[key]);
    ]]>
    </fx:Script>
</s:Application>
Can you test this code in yours computers?
Anybody know where is a problem? I don't have any applications run in background. etc...
Testes on SDK: 4.0 (default in Flash Builder 4 b 2), 4.0 build 13875, 4.1 build 14741
Mariusz Dalewski

Answer 1

Here are my results with a few classes:
spark.components.Group:
0 - 87676
1 - 10563
2 - 340
3 - 346
4 - 349
5 - 480
6 - 222
7 - 6
8 - 4
9 - 1
10 - 1
11 - 1
76 - 1
13 - 1
14 - 2
16 - 1
12 - 1
407 - 1
472 - 1
26 - 1
94 - 1
31 - 1
mx.containers.Canvas:
0 - 79601
1 - 18534
2 - 287
3 - 258
4 - 284
5 - 383
6 - 328
7 - 243
8 - 42
9 - 11
130 - 1
11 - 2
324 - 1
13 - 2
14 - 3
10 - 3
18 - 1
12 - 9
21 - 1
741 - 1
504 - 1
27 - 2
28 - 1
351 - 1
mx.core.UIComponent:
0 - 89460
1 - 8748
2 - 337
3 - 382
4 - 317
5 - 527
6 - 209
7 - 3
8 - 2
9 - 3
42 - 1
99 - 1
12 - 1
462 - 1
14 - 2
15 - 1
116 - 1
118 - 1
124 - 1
30 - 1
31 - 1
Sprite:
0 - 98957
1 - 1030
2 - 1
5 - 11
6 - 1
spark.primitives.Rect:
0 - 99598
1 - 402
spark.primitives.supportClasses.GraphicElement:
0 - 99598
1 - 402
As Bonzo mentioned this doesn't seem to be a Group problem as Canvas also has some long times.  UIComponent is lighter than both Canvas and Group and it still has  a couple entries longer than a few ms.  Notice that using Sprite or GraphicElement is much faster.  GraphicElement is very lightweight, are you able to use it instead of a Group? 100,000 Groups seems like a lot, can you explain your use case, maybe there is a way to use virtual layout to minimize the number needed at any one time?
I think the container.push() call might be causing a lot of the delay, if you use:
private var container:Array = new Array(100000);
container[i] = grp;
You should see less large delay times.  It might be good to try using a Vector instead of an Array like Bonzo suggested too.