ASP.NET Site Performance Secrets

Categorizing bottlenecks using Waterfall charts

Before we saw how to create a Waterfall chart with Firebug, we discussed the four broad categories of bottlenecks that slow down page loading:

• Main .aspx file taking too long to generate
• Main .aspx file taking too long to load
• Images (and flash files) taking too long to load
• JavaScript and CSS files blocking page rendering

The following sections show how each broad category expresses itself in a Waterfall chart generated by Firebug. Each section also refers you to the chapter where you'll see how to further pinpoint the bottleneck and then fix it.

Scenario 1: Main .aspx file takes long to arrive

In the chart below, the top line is for the main .aspx page. The purple section shows how long the browser waited ...