Speed is one way Google can make Chrome more appealing to Windows users in the face of competition from Microsoft’s Windows 10 Edge browser.
For its latest effort to make Chrome faster, Google turned to Microsoft’s implementation of Profile Guided Optimization (PGO) to cut Chrome’s new tab page load times by 14.8 percent, page load times by 5.9 percent, and start-up times by 16.8 percent.
The PGO-based speed improvements are available in 64-bit Chrome on Windows since version 53, which Google released at the end of August, and this week’s version 54 for 32-bit Chrome.
PGO is one way to optimize compilers by identifying which functions of a program are less or more frequently executed during runtime.
Developers can build a special version of the app and put it through its paces under common user-interaction scenarios. The results inform how best to optimize the app. The tool is available with Microsoft Visual Studio, which has supported PGO since Microsoft Visual C/C++ 2005.
It’s not clear whether this is the first time Google has used the tool to improve Chrome on Windows, but the search firm notes it can be helpful for a software project as large as Chrome, which has more than a million functions in its source code.
Google’s optimization process is focused on its nightly Chrome build process, which uses a special version of Chrome to track function usage.
“PGO then optimizes those high-use functions for speed, in some cases increasing the binary size of those functions. To balance out that increase, PGO also optimizes less-used functions with smaller, though slightly slower code. These trade-offs result in higher overall performance, and a smaller overall code footprint,” explained Google’s Sébastien Marchand.
According to Marchand, PGO-derived memory optimizations are also helping deliver overall performance improvements in Chrome. It does this by moving rarely-used functions away from frequently-used ones.
“This results in more optimal use of the CPU instruction cache by avoiding caching of less-used code, increasing overall performance,” said Marchand.