The 20-line patch works by preloading Firefox’s XML Markup Language (XUL) library. Whereas previously that library was loaded in chunks of 32KB or less, the patch works by “tricking” Windows into preloading the library in 2MB increments instead, Mozilla developer Taras Glek explained recently on Mozilla’s Bugzilla forum.
The patch shaved two seconds off of the browser’s startup time in Glek’s initial trial–representing a performance improvement of 40 percent–but the results were even better on a machine with a slow hard drive.
“Shaved around 50 percent off cold startup on my reference slow system,” he wrote. “This patch works better than I expected. Not only does it trade random xul.dll io for faster sequential io. It also reduces the amount of seeks later on (ie no need to seek for xul bits), which significantly speeds up io on other files.”
The Need for Speed
In Firefox’s competition with Google’s Chrome and Microsoft’s Internet Explorer browsers, speed has become a pivotal factor.
With 23 percent of the browser market in December, Firefox holds the No. 2 position in that arena, following only Internet Explorer, which accounts for 57 percent, according to the latest data from researcher Net Applications.
While Microsoft’s share last month represented a decline from the 58 percent it held in November, Firefox enjoyed a small increase over the 23 percent it held in November, Net Applications reported. Firefox was also recently named the No. 1 browser in Europe by research firm StatCounter.
Slated to appear soon in a Firefox 4 nightly build, the feature could ultimately make its way into the browser’s next official version, which is due next month. If that happens, it could give Firefox another boost ahead of the competition.