Google Chromium startup is up to 25.8% faster And 4.5% fewer accidents compared to the past, and that not today but more than a year ago. It is not we who say it but the Mountain View house itself, inside a long post who talks about the project Native window occlusion and its effects on browser performance.
From version 86 released in October 2020Google has implemented in the stable version of Chrome a feature called “occlusion“, occlusion. By analyzing users’ browser usage behavior, the company found that “nearly 20% of Chrome windows are completely covered by other windowsthat is to say, they are occulted”.
The company has deprioritized background tabs for several years to improve the user experience: for example, in background tabs, JavaScript is restricted and web content is not displayed. “This reduces CPU, GPU, and memory usage, leaving more memory, CPU, and GPU for the foreground tabs the user is viewing.”
Logic was limited to tabs that were not in the foreground or those minimized or otherwise moved off-screen, but this did not apply to occluded. So Google, about three years ago, started working on a project to track the occlusion status of every Chrome window in real time and de-prioritize tabs in occluded windows.
Windows doesn’t provide a direct way to tell if a window is completely covered by other windows, so Google had to scramble to find a workaround. We’ll spare you the explanation of the process of getting the fix, but they succeeded and implemented occlusion in Chrome 86, a version released over a year ago.
“Our results show significant performance gains” with the feature enabled, explains the developer, outputting various data as a “Startup 8.5% to 25.8% faster“, a “3.1% reduction in GPU memory usage”, and “4.5% fewer render crashes”. The reason they improve startup performance is because, as explained developer David Bienvenu, “When Chrome restores two or more full-screen windows on startup, it’s likely that one of the windows is obstructed. Chrome will now skip most of the work for that window, saving resources for the foreground window.”