Speculation Rules Prefetch — Dashboard

bug 1969396 — [meta] Implement Speculation Rules – Prefetch (Same-origin)

Telemetry

Use counters — Redash

Live sites

Browsertime navigation tests against live sites that ship speculation rules.

symfony.com — blog sub-navigation List rules. Sub-navigation LCP 71 ms, vs 342 ms with rules disabled.

CI

Raptor browsertime on autoland · navigation_duration, lower is better · Firefox vs Chrome · from 2026-06-30

Rule source List rule Document rule

Platform

Range 7 days 30 days 90 days

daily median overlay log scale

Reading the numbers: the test server stalls target.html by TARGET_STALL_MS = 500 (the p75 top-level document response time on desktop). A prefetch-cache hit skips that wait and lands around 15–25 ms; a miss pays it in full and lands at 520 ms or more. So the two regimes are far apart, and which one a series sits in is the result.

Data source: Perfherder (repository autoland, framework browsertime) — the task's run-on-projects is autoland-only, so no other branch has this data · Raptor docs · bug 2007155 (perf tests) · test pages