Profiling add-ons in firefox

Question

One new feature of ie9 I like is that it alerts you to which add-ons are making your browser run slowly. Is there a way to get access to similar information in firefox?

Answer 1

There is no way currently for Firefox to profile it's extensions without a significant overhead due to the way the Extensions API is built.

This extension will tell you a bit more about your startup times: About Startup

And Mozilla conducts regular tests on the addons every week. Here's the listing of the slowest addons (updated weekly)
_{editor's Note: it appears that Mozilla is no longer publishing this.}

And if you want more info from the mozilla team, here you go and here.