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Fixing Firefox

When the Mozilla development team started work on Firefox 3 back in 2005, one of the key issues facing the group was the issue of memory management. Shifting usage patterns and increasingly demanding Web environments had exposed issues like insidious memory leaks and application processes that failed to let go of allocated memory. The result: Degrading performance and concerns about stability.

About a month ago, Mozilla developer Stuart Parmenter wrote an informative account of how his team went about attacking the memory allocation and handling problem. You can read it on his blog here.

I spoke with Stuart and with Mozilla Vice President Mike Schroepfer yesterday about the Firefox 3 development process. To improve memory performance, the team had to go beyond tweaking their code and build custom tooling to help them measure and address the challenge. It wasn't a trivial task, Parmenter said.

"I would say it was pretty difficult. We had to take a look at a pretty low level at what was going on. So we actually had to end up building a lot of custom tools to monitor when our our memory was being allocated, how it was being allocated, how it was being freed and what the result of that was," Parmenter explained. "So a lot of really deep technical issues there. We built a lot of tools to measure that."

The results are apparent to many users working with the current beta 4 of Firefox 3, but Parmenter's blog post offers pretty compelling quantitative results, as well. His team cooked up an aggressive series of tests that reflect the evolving nature of Web browsing, and measures how well the code behaves when juggling multiple sites in multiple tabs over a long period of time. According to their tests, Firefox 3 does a much better job of releasing memory, with a terminal state that's 60 percent below that of Firefox 2.

What might it all mean for corporate developers and managers? Parmenter and Schroepfer said that all development efforts can benefit from the kind of continuous build process that's been in place at Mozilla throughout the Firefox 3 effort. The team produces nightly builds of Firefox, Schroepfer said, and has kicked out eight alphas and four public betas in the time that Microsoft has produced one public milestone of Internet Explorer 8.

What are your impressions of the latest Firefox beta? Is the Mozilla team onto something, and can we all learn something from them? E-mail me at [email protected] and let me know why or why not.

Posted by Michael Desmond on 03/20/2008 at 1:15 PM

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