Felix Fung once said something along the lines that main-thread IO should only be dealt with by tossing it in to a woodchipper, making mushroom fricassee with it, microwaving it, and then butchering it up some more.

Today marked the completion of Felix’s internship at Mozilla. While sad to see him go, I’m happy to say that Felix did an amazing job at removing some of the main-thread IO found in Firefox, thus making Firefox even faster.

For example, in Firefox Aurora (soon to be Firefox 10), downloads in the browser now use considerably less CPU usage (sometimes reduced by ~50%).

Another great fix came in for about:permissions . Users who had many thousands of sites listed in about:permissions would encounter sluggish behavior from the browser when loading about:permissions . This sluggish-ness is now a thing of the past that should be long forgotten and never missed.

In Firefox Nightly (soon to be Firefox 11), we now have a complete internal asynchronous API for favicons. Work had started on this in earlier releases, but it has now reached completion. The landing of this feature will allow consumers of favicons (think of: tabs, history, bookmarks, downloads, Windows 7 jump lists, I-don’t-know-what-else-but-there-are-probably-tons-more, etc) to render, react, and update much quicker.

Felix (wearing the plum dress shirt) wasn’t the only intern in Mountain View during the Fall. See the picture to the right for a group of smart, funny, and hard-working interns who have been working to make the internet better for all.