Diagnostics Tools

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You can monitor performance and memory using diagnostics tools. Let’s look at a few of them.

Hi-Res-Stats

The Hi-Res-Stats class, from mrdoob, calculates the frame rate, the time to render each frame, the amount of memory used per frame, and the maximum frame rate and memory consumption. Import the library and add a new instance of Stats as a displayOb ject. This is simple and convenient to use (see https://github.com/bigfish):

[code]

import net.hires.debug.*;
var myStats:Stats = new Stats();
addChild(myStats);

[/code]

Because it needs to be added to the displayList and draws its progress visually, as shown in Figure 19-4, this tool may impact rendering slightly, or get in the way of other graphics. A trick I use is to toggle its visibility when pressing the native search key on my device:

[code]

import flash.ui.Keyboard;
import flash.events.KeyboardEvent;
stage.addEventListener(KeyboardEvent.KEY_DOWN, onKey);
function onKey(e:KeyboardEvent):void {
switch (e.keyCode) {
case Keyboard.SEARCH:
event.preventDefault();
myStats.visible = !myStats.visible;
break;
}
}

[/code]

Figure 19-4. Hi-Res-Stats display
Figure 19-4. Hi-Res-Stats display

Flash Builder Profiler

The premium version of Flash Builder comes with Flash Builder Profiler, which watches live data and samples your application at small, regular intervals and over time. It is well documented. Figure 19-5 shows the Configure Profiler screen.

Figure 19-5. The Configure Profiler screen in Flash Builder Profiler
Figure 19-5. The Configure Profiler screen in Flash Builder Profiler

When “Enable memory profiling” is selected, the profiler collects memory data and memory usage. This is helpful for detecting memory leaks or the creation of large objects. It shows how many instances of an object are used.

When “Watch live memory data” is selected, the profiler displays memory usage data for live objects. When “Generate object allocation stack traces” is selected, every new creation of an object is recorded.

When “Enable performance profiling” is selected, the profiler collects stack trace data at time intervals. You can use this information to determine where your application spends its execution time. It shows how much time is spent on a function or a process.

You can also take memory snapshots and performance profiles on demand and compare them to previous ones. When doing so, the garbage collector is first run implicitly. Garbage collection can also be monitored.

Flash Preload Profiler

The Flash Preload Profiler is an open source multipurpose profiler created by Jean- Philippe Auclair. This tool features a simple interface and provides data regarding frame rate history and memory history, both current and maximum.

Other more unusual and helpful features are the overdraw graph, mouse listener graph, internal events graph, displayObject life cycle graph, full sampler recording dump, memory allocation/collection dump, function performance dump, and run on debug/ release SWFs capability. More information on the Flash Preload Profiler is available at http://jpauclair.net/2010/12/23/complete-flash-profiler-its-getting-serious/.

Grant Skinner’s PerformanceTest

Grant’s PerformanceTest class is a tool for doing unit testing and formal test suites. Some of its core features are the ability to track time and memory usage for functions, and the ability to test rendering time for display objects. The class performs multiple iterations to get minimum, maximum, and deviation values, and it runs tests synchronously or queued asynchronously.

The class returns a MethodTest report as a text document or XML file. It can perform comparisons between different versions of Flash Player and different versions of the same code base. More information on this class is available at http://gskinner.com/blog/ archives/2010/02/performancetest.html.

Native Tools

The Android Debug Bridge (ADB) logcat command grabs information from the device and dumps it onto a log screen via USB. A lot of information is provided. Some basic knowledge of the Android framework will help you understand it better.