enricobuehler
a11c672bea
The Android HUD headlined `capture→displayed` with SurfaceFlinger's latch
and scanout inside it — pipeline depth no client can pace under. The usual
Android streaming overlays stop measuring at decode-complete, so users
comparing overlays read our honesty as latency: on a 60 Hz panel that floor
alone clears 30 ms, more than everything those overlays display put together.
Exclude it, the way the Apple clients have since the presentation rebuild
(8a40e467): shave the measured floor off the shown display and end-to-end at
every tier, and name what came off in Detailed as `os present +N excluded
(display pipeline minimum)`. The equation still tiles the headline, because
the `display` term is shaved by the same amount.
The floor is the `latch` p50 we already measure (release→OnFrameRendered),
not a modelled 2/refresh: it moves with the panel rate, tunnelled playback
and the vendor's low-latency mode, and it exists on every render path (the
release stamp is parked on all three), so it does not depend on the timeline
presenter being active. Unmeasured reads 0.0 and nothing is shaved — we
exclude only what we actually measured. With the floor out, the `display`
term is already just `pace`, so the `(pace + latch)` split now renders only
on a window where no latch sample paired, and the hardcoded 2-refresh
Apple-equivalence twin is gone with it.
Raw numbers are untouched in the 1 Hz `pf.present` logcat line, so HUD-off
A/Bs and cross-session comparisons still read unshaved values.