Firefox 3.5's TraceMonkey and the Importance of Native Code

Google has just announced it will begin to integrate its Native Client technology with its Chrome browser but that doesn't mean that it's the only one doing it. In fact Mozilla is already offering a similar technology in its Firefox 3.5 browser. Called TraceMonkey, the technology translates commonly used JavaScript code into native machine code, bringing a huge increase in performance with it. And, as part of the “Firefox 3.5 in 35 days” program Mozilla has been running, it has put together a demo showcasing TraceMonkey.

The importance of native code cannot be overstated. As web apps are replacing desktop apps and network speeds make cloud software a real possibility and alternative, there has been a big issue holding further expansion. Web apps are considerably slower than desktop apps written in native machine code. This is because most online apps are written in JavaScript, which, like any scripting language, has to be interpreted, 'compiled' on the machine every time the app is run.

This hasn't been such a problem in the past but as web apps are becoming more prevalent and doing more complex jobs the speed disadvantage has been a major issue. Of course, JavaScript interpreters' performance can be enhanced, and all major browsers have been making tremendous improvements on that side, but this can help them only so much.

TraceMonkey is somewhere between a JavaScript interpreter and a normal binary application compiler and it is different from what Google is doing with its Native Client technology. TraceMonkey will compile certain parts of the JavaScript code into binary code but not the whole application. This was chosen as the best compromise between performance and resource consumption. The engine will analyze and trace the software as it runs and will compile only the most commonly used parts, speeding up the applications but keeping requirements low.

All of this may sound very good but a much better and impressive way of understanding the technology is seeing it in action. That is why the development team put together a demo that should give you a pretty good idea of the speed improvements. However, if you don't have Firefox 3 and Firefox 3.5 installed at the same time you can watch a video made by the Mozilla developers and posted on their blog, embedded with the HTML 5 'video' tag of course. Or you could just download the browser from here.