Google is currently making a concerted effort to make its Chrome browser faster and leaner. The company announced a project to bring down memory usage earlier this month, for example. But it also quietly started work on some otheroptimizations recently, too, thatadd up to making Chrome on Windows run about 15 percent faster than before.
Starting with theChrome 53 release of64-bit Chrome and version 54 of the 32-bit version, Google started using Microsofts so-calledProfile Guided Optimization technology to speed up startup times (by 17 percent), new tab page load times (by almost 15 percent), and overall page load times (by 6 percent) in Chrome.
Profile Guided Optimization (PGO) is a feature of Microsofts Visual Studio developer tools that measures how users actually interact with an application. It then uses this training data and re-compiles the applicationwith a focus onoptimizing the most often used functions of the application.
Chrome is a huge software project with more than a million functions in its source code, Googles Sbastien Marchand explains in todays announcement. Not all functions are equal some are called frequently, while others are rarely used. PGO uses data from runtime execution that track which functions are most common to guide optimization.
One of the most effective techniques PGO uses to speed up applications isto optimize where in the memory the often-used functions are kept so at least in the ideal situation those functions can be kept in the CPUs fast instruction cache.
You can read all about how PGO works in practice here, but the main takeaway is that Google is still able to squeeze more performance optimizations out of its existing code base for Chrome. Given that PGOisnt exactly new, though, it does come as a bit of a surprise that the team didnt use this techniquealready.