Interestingly, on my rather slow Windows 7 laptop the delay caused by Adblock Plus is still 100ms despite a regular Firefox startup taking 800 ms. So “20% slower startup” means 100-150 ms delay.
Right now there are four machines running the tests, on Windows XP, Windows 7, Mac OS X 10.5.8 and Fedora Linux 12.I couldn’t find the configuration files used to run add-on tests but I could find the raw test results under (you have to go a few days back, the last round of tests ran on April 2nd).
So I got Talos source code from and looked around. Adblock Plus for example already follows all the Performance Best Practices that apply to it, how comes it is supposedly degrading Firefox startup performance by whooping 21%? What is being measured there, how, under which conditions? How much delay are we talking about, in absolute numbers? I can however imagine many developers being not too happy right now, and not only because of more attention to the shortcomings of their add-on. So everything is progressing nicely towards the goal - pressure on developers starts building up, I already had something like 10 people point out to me that Adblock Plus is number 12 on that list. Some media already picked up on that article and users are listening up. It comes complete with a list of worst offenders. Mozilla Add-ons recently published an article on their effort to recognize slow add-ons. Adblock Plus and (a little) more Some more details on Mozilla's add-on performance measurements