Flash Builder 4 Profiler: how to spot what objects are causing a known memory increase?

Question

I know profiler questions can be quite general, but here I have a very specific question and example.

I know that in the following code (taken from Joshua\'s questio

Answer 1

1. Run the application using Profiler (choose the option to Generate object allocation trace when asked)
2. Take two Memory Snapshots af few seconds apart
3. Select both of the Memeory Snapshots and click Find Loitering Objects
4. Make sure to click Filtering, and remove any filters
5. Sort by memory. UIComponent will be top/close to top of the list
6. Double click UIComponent in the Loitering Objects window - this brings up Object References window.
7. Click a UIComponent under Instances and view its Allocation Trace, this will let you know where that UIComponent was created (if you double click on the Allocation Trace view where it gives you the line number - 30 in this case - it opens that location in Source view).

Now you know the source of the memory problem

To fix the accumulative memory leak, add the following:

After fadeEffect.play(); add

fadeEffect.addEventListener(EffectEvent.EFFECT_END, onEffectEnd);

and add the function:

private function onEffectEnd(event:EffectEvent):void
{
   trace(hostComponent.numChildren);
   hostComponent.removeChild(event.target.target);
   event.target.target = null;
}

Answer 2

First, I would look at the Memory Usage panel after playing a bit with the application :

Notice the memory increases more and more. There is a "Run Garbage Collector" button that forces the GC. However, when you click on it, the memory doesn't decrease.

The next step is to identify the culprits. For that, you use the Live Objects panel :

It looks like that, appart some Vector instances, everything looks allright. By default, a lot of classes are filtered from the live objects datagrid. Fortunately, one can specify which classes will be displayed and hidden. All classes from the flash.x.x packages are hidden by default. Removing them from the filtered list bring somthing interesting to the table :

Notice the Graphics row : 871 instances have been created and they are all still in memory! With that info, you can suppose the Graphics instances are responsible of the slow down of the application. If you also filter out the mx.* classes, you will see there are 871 UIComponents instances. Everytime a UIComponent is created, there is a Graphics object also instancied.

Final step is to remove each UIComponent once it's no more needed on screen and look if there is any performance improvement.