Google has implemented significant improvements in Chrome for Android, resulting in a 48% reduction in what is known as 'scroll jank,' making the scrolling experience smoother for users.
Understanding the 'Scroll Jank' Problem
This type of instability is a common behavior, but one that is now less frequent, where the scrolling flow appears to momentarily stop. In certain situations, the browser may exhibit a 'jump,' abruptly advancing to a more distant point on the page, making it difficult to locate specific information.
Google clarifies that this jump occurs due to a time limit Chrome has to display each frame before screen refresh. If this limit is exceeded, the previous frame remains visible for an additional refresh cycle. When the new frame is finally ready, the page jumps directly to the most updated scroll position.
Although users perceive this dynamic as a visual 'stutter,' the problem is considered more subtle than a complete freeze. Therefore, Google focused its efforts on reducing this 'scroll jank.'
How the Improvement Was Achieved
The solution was not limited to just speeding up Chrome, but rather ensuring that the frame delivery flow was as consistent as possible, given that various factors can cause this instability. Developers modified how Chrome manages touch inputs related to scrolling.
Instead of overloading the browser's main task—which might be busy executing scripts—the scrolling processing was transferred to a more specialized and consequently less prone to delays component. Additionally, Chrome began optimizing the frame display time.
If a small delay of a few milliseconds occurs in a touch, the browser chooses to wait a bit before rendering the next image. If the remaining time is insufficient, the system estimates the position the finger should reach at the subsequent moment, preventing the screen from repeatedly displaying an old frame and generating the 'stutter' effect.
Results and Future Perspectives
As a result of these optimizations, Google reports that 'scroll jank' has been reduced by 48% in Chrome for Android between 2023 and 2026. Although the article's author expected a higher percentage, they consider this advancement relevant, considering the vast diversity of devices and configurations on which Chrome for Android operates. Google indicated that optimization work on Chrome for Android will continue.
