Chrome 91 Is 23% Faster Thanks To These Changes

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Last week Google rolled out the Chrome 91 update on the stable channel. The latest version of the browser introduces tons of new features and improvements including support for default desktop mode on large screen devices, revamped controls, and the ability to freeze Tab Groups. But, apart from the new features, the update also brings some performance improvement under the hood. According to the company, Chrome 91 is 23 percent faster than the previous version, thanks to some underlying changes.

Fast JavaScript execution is an “important component” for delivering a fast browsing experience. The V8 engine handles that job in the Chrome browser. It executes “over 78 years’ worth of JavaScript code on a daily basis,” Google said in a recent post on the Chromium blog.

With Chrome 91, the company has made some improvements to the V8 engine that enabled a significant performance boost. Specifically, Google has introduced “a new Sparkplug compiler and short builtin calls”. This apparently saves “over 17 years” of CPU time for Chrome users each day.


Google promises faster performance with Chrome 91

In May 2017, Google introduced a two-tier compiler system in the V8 engine consisting of Ignition and Turbofan for JavaScript execution in the Chrome browser. Ignition is responsible for quickly starting executing the JavaScript while Turbofan optimizes the code for maximum performance. The compilers make different tradeoffs throughout the various phases of JavaScript execution.

Turbofan depends on information gathered during JavaScript execution for generating high-performance machine codes. This results in a slower start-up than Ignition, delivering a slower browsing experience. The newly introduced Sparkplug is a new JavaScript compiler that fills the gap between these two phases. It does not depend on information gathered while executing the JavaScript for generating native machine codes. This allows for quick execution while generating high-performance codes faster.

Short builtin calls, meanwhile, enable the V8 engine to optimize the location in memory of generated code to avoid indirect jumps when calling functions. Thomas Nattestad, Chrome Product Manager, explains that when a CPU-specific code is generated from JavaScript, the V8 engine lays that code out in memory. This code calls builtin functions that handle common routines.


However, for some CPUs, “calling functions that are further away from your generated code can cause CPU-internal optimizations to fail,” Thomas writes in the blog. With Short builtin calls, the builtin functions are copied into the same memory region as the generated code. This will avoid those optimization failures.

In simpler terms, these are some underlying changes that make the Chrome browser faster than it was before. If you want to know more about the technicalities of these changes, you can head over to the V8 blog. Google says there are more improvements to come for its browser.