frameclock_wayland: add present-time estimator - #44
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no-materials merged 1 commit intoJul 2, 2026
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Replace the subduction_backend_wayland present-hint stub with a real estimator in frameclock_wayland. TickerState now retains the last observed refresh interval alongside the actual-present time and predicts the next vsync at or after the tick time, so emitted FrameTicks carry a real predicted_present/refresh_interval once wp_presentation feedback flows. New present_hints, present_hints_with_commit_lead, default_commit_lead, and display_timing free functions mirror the Apple and Web adapters; a predicted time is reported as Estimated, since it is a client-side vsync-grid extrapolation rather than a compositor-provided target, and falls back to pacing-only when no feedback exists. The backend feeds the observed refresh interval to the ticker at the wp_presentation_feedback.presented sites, the hints.rs stub is removed, and the wayland_layers and wayland_lotta_layers examples are repointed to the new helpers and paired with SchedulerConfig::estimated().
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This looks interesting, but I think the best way to see about it will be to get a few things landed so that you can try writing a |
waywardmonkeys
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Jun 29, 2026
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I don't really have a way to test / confirm this ... I'm inclined to land it and let people test it by having it be usable via Overstory (at least).
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Replaces the
subduction_backend_waylandpresent-hint stub with a real present-time estimator inframeclock_wayland, matching the Apple/Web adapter shape.TickerStatenow retains the last observed refresh interval next to the actual-present time and predicts the next vsync at or after the tick time, so emittedFrameTicks carry a realpredicted_present/refresh_intervaloncewp_presentationfeedback flows. New free functionspresent_hints,present_hints_with_commit_lead,default_commit_lead, anddisplay_timingconsume that tick: a predicted time is reported asEstimated(a client-side vsync-grid extrapolation, not a compositor-provided target) and falls back to pacing-only when no feedback exists yet.The backend feeds the observed refresh interval to the ticker at the
wp_presentation_feedback.presentedsites and the oldhints.rsstub is removed; thewayland_layersandwayland_lotta_layersexamples are repointed to the new helpers and paired withSchedulerConfig::estimated().