Previously, the rendering tasks (i.e. BeginMainFrame) were always run at default priority on the main thread. This means that rendering could be starved by other normal priority work, for example tons of postMessages ( This feature is an internal scheduling change which prevents this from happening by periodically increasing the priority of rendering if we have not rendered in a while. It targets a lower frame-rate of 10 fps.


Specification link

Proposal in a personal repository, no adoption from community

Status in Chromium


Enabled by default (tracking bug)

Consensus & Standardization

After a feature ships in Chrome, the values listed here are not guaranteed to be up to date.

  • No signal
  • No signal
  • No signals


Intent to Prototype url

Intent to Prototype thread


This entry is meant to serve as an FYI of an underlying change which could impact timing.

Search tags

scheduling, rendering, prioritization,

Last updated on 2021-12-13