The changes were detailed in a post on the Chromium blog, a site that provides information on the open-source browser engine behind Chrome. Starting from Chrome 53, Google has managed to boost overall performance by up to 15 percent by optimising the way in which code runs.
The speed increase comes from Google’s use of Microsoft’s Profile Guided Optimization (PGO) for the first time. The technology, a part of Microsoft’s Visual Studio developer tools, is able to intelligently monitor how an application’s code is used. Essentially, it works out how users interact with the program and then compiles it so the most frequently accessed parts are optimised.
Google has incorporated this into its nightly build tools when generating new Chrome versions. The compiler now tracks how often functions are called in the code and optimises the high-use ones for speed. In some cases, this can raise the size of the code. PGO offsets this by optimising less-used functions with smaller but slightly slower code. Overall, this creates a more performant code base with a smaller size.
“Chrome is a huge software project with more than a million functions in its source code,” said Google. “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.”
The changes have led to speed improvements in some of the most noticeable areas of Chrome. Google has observed the new tab page loading up to 14.8 percent faster. Browser startup time has been increased by up to 16.8 percent and the page loading process now completes 5.9 percent more quickly. The performance gains will deliver a noticeable boost to how Chrome runs on low-end machines.
Recently, Google has been striving to optimise Chrome to improve performance across the board. After gaining a reputation for being taxing on hardware including the CPU, memory and battery, the company has begun to strip out the bloat and create a leaner and faster experience. The results are now beginning to pay off. The integration of PGO will continue Chrome’s progression to being a lightweight, highly performant web browser that runs well on any machine.
In December, Google will deliver another significant speed boost to Chrome by upgrading its V8 JavaScript engine in Chrome 55. It has optimised V8’s memory management and JavaScript usage to reduce the RAM consumption of the browser. In some cases, the company has observed a 50 percent cut in usage, making Chrome far more responsive on low-end devices.
