Interaction to Next Paint Changes in Chrome 134

Defer non-urgent renderer tasks after input by default

To ensure user input is processed with minimal delay and interactive frames are rendered promptly, Chrome 134 enabled DeferRendererTasksAfterInput (policy kAllTypes) by default.

When user input is received, Chrome temporarily defers non-urgent main-thread tasks (such as background timers and non-critical queued work) until after the visual response to the input has been composited and presented to the display.

This optimization ensures that the browser does not interleave unrelated JavaScript execution or housekeeping work between the event handler's completion and the presentation of the next frame.

The source change can be found in crrev.com/c/6175333.

How does this affect a site's metrics?

INP improved on all platforms with this experiment.

This change led to a broad, positive shift in real-world INP scores across the web without requiring any changes from site developers!

• Lower field INP: Sites with heavy main-thread activity or many queued background tasks experience less queueing delay between event dispatch and next paint, resulting in lower (better) INP at the 75th and 95th percentiles.
• Metric stability: Reduces tail latency variance caused by background timer callbacks executing right after user interactions.
• Cross-platform benefit: Applies globally across all desktop and mobile platforms.

When were users affected?

Chrome 134 reached stable users in January 2025.