Simple Profiling Example

This example begins by creating a namespace:

This namespace serves as the core object upon which others will be added (to prevent creating global objects).

Next, an object is created with a method:

This object, MathHelper contains a single method called factorial() that computes the factorial of a given number. Any time factorial() is called, the argument indicates how many times the function will be recursively called. For example, factorial(10) results in the funtion being called 10 times. This makes it an ideal test case for profiling because the results are so predictable.

Registering the function

The most important step to profile this function is to call registerFunction() with the fully-qualified function name, which is YAHOO.example.profiler.MathHelper:

Since this function is fully accessible in the global scope, there's no need to provide the owner object as the second argument.

Running the example

With everything setup, the last step is to run the code. This initialization is assigned to take place when the document tree has been completely loaded by using the Event utility's onDOMReady() method:

The code block begins by calling factorial() once, which gets profiled. Then, the information about the function can be retrieved from the Profiler. This information is output into the Logger on the page, displaying the number of times that the function was called along with the minimum, maximum, and average running times. Since this is a very simple function, the run times will most likely be 0ms on most machines.

Configuration for This Example

You can load the necessary JavaScript and CSS for this example from Yahoo's servers. Click here to load the YUI Dependency Configurator with all of this example's dependencies preconfigured.