Measuring Front End Performance

Before getting all worked up and diving into back end performance, please please please take some time to look at whats happening on the front end. Chances are you'll have little to no work to do once you get get done with the front end (at least not right away). There are two types of front end performance: actual and perceived <link to UIE study here>. In most cases, you don't give a crap about actual performance, however, its almost impossible to measure perceived performance and since we know we shouldn't do anything without measurements first, well, thats the only place to start. Here are some tools to get started:

• Google Page Speed (the stepchild of of YSlow) is the main tool you need to use, understand, believe, and follow through on. Most of the tips in the front end performance section are lifted from using this, yslow, and believing what @souders says. If you are really dedicated buy his book or at least see him talk. Its more than enough to get you started and most changes he talks about are easy breazy.
• The online version of this is WebPageTest.com.