JavaScript speed boost ahead for Mozilla's Firefox

Stephen Withers
Tuesday, 26 August 2008 03:52

Business IT - Open Source

Web applications are set for a speed boost, but it's nothing to do with their developers. The TraceMonkey project is hard at work on a new and much faster implementation of JavaScript for the Firefox browser.

While TraceMonkey is still in its early stages, the target is to make it a part of Firefox 3.1, which is expected in late 2008 or early 2009.

TraceMonkey already performs various benchmarks in 4.5 percent to 55 percent of the time taken by Firefox 3, and useful further improvements are thought possible.

"The goal of the TraceMonkey project - which is still in its early stages - is to take JavaScript performance to another level, where instead of competing against other interpreters, we start to compete against native code," wrote Mike Shaver, interim VP engineering at Mozilla. "Even with this very, very early version we’re already seeing some promising results: a simple 'for loop' is getting close to unoptimized gcc."

gcc is the GNU Compiler Collection, widely used for open source and commercial software development. Shaver's observation compares code written in JavaScript and C.

Mozilla CTO and original JavaScript creator Brendan Eich explained that SpiderMionkey gets its speed from a new kind of just-in-time (JIT) compiler.

Where a conventional compiler converts entire programs into machine code at the outset, JIT compilers convert sections of the source code that are executed often enough to make it worth the effort. This much of the performance of a full compiler without the initial overhead.

So where does SpiderMonkey get its speed? Please read on.