Ramin Hossaini (blog)

Firefox 3.1b1 Pre + TraceMonkey

Just downloaded the latest BETA release from Mozilla (codenamed "Minefield" - scary) and to my (pleasant) surprise, it comes with an optional TraceMonkey engine.

For you that don't know what TraceMonkey is, it's an optimization added to SpiderMonkey. Sounds like a lot of monkeys. But it offers between 20 and 40 times faster Javascript speeds.

To enable TraceMonkey:

• Go to the about:config page, and click on the button to get past the warning message
• Enter jit in the field
• Enable both entries to true. (javascript.options.jit.chrome and javascript.options.jit.content)

Firefox now gets an 84/100 for the Acid 3 test (Google Chrome scores a 78/100)

I ran a quick javascript-speed-test between Google Chrome and this new version of Firefox*.

• Google Chrome finished the test in 160ms. Impressive.
• Firefox comes in close at 205ms
• Internet Explorer 7 finished in 1008ms. I'm pretty sure IE8 beta does better than that though.

* your mileage may vary

Workaround: Mozilla release Shiretoko; messes up my extensions

Mozilla released Firefox 3.1 alpha 2 which adds some interesting new features.

• An improvement on the Acid 3 test, now scoring 83/100.
• Internal tab-switching (using CTRL-TAB)
• Initial support for web worker threads, which improves Javascript support for certain scenarios.

Great! Only problem is - most of my add-ons stopped working.

Annoying - chances are, if the add-on was supported in Firefox 3.0, it might just work in 3.1a2.

So... to bypass the add-on compatibility-check:

• On Windows XP, navigate to C:\documents and settings\[username]\application data\Mozilla\Firefox\profiles\[random folder]\extensions
• On Windows Vista, navigate to C:\Users\[name]\AppData\Roaming\Mozilla\Firefox\Profiles\lmqbc2av.default\extensions
• If you can't find the folder, try a file-search for install.rdf
• Each folder in the above-location is associated to a Firefox extension.
• Open a folder and edit the install.rdf file.
• the install.rdf file is really an XML file - look for "maxversion". I changed the value to "3.1.*"

Note: There might be another (cleaner) way of getting around this problem. The about:config page used to have an extensions.checkCompatibility variable which could be set to ignore these, but it has been taken out in this release.

Note 2: I've tried this out with the Delicious, StumbleUpon, Better Gmail, and Firebug extensions and have had no problems, but I can't guarantee that it will work for you.

Note 3: This hack will most likely work for lots of up-coming releases of firefox.

Note 4: I would probably activate each one of the add-ons one-by-one just to see everything works properly. If it crashes the browser, you can just revert/undo the changes you made and wait until a new version of the add-on comes out.

I love browser-wars.