A sched trace on the TV (release build) caught the real "2fps": not a
slow frame, but a starved one. During navigation the render pipeline
(app RenderThread, SurfaceFlinger/RenderEngine, the mali driver worker,
the Dolby audio service) saturated all four cores together with Coil's
image work — a burst of parallel ~30 ms bitmap decodes split across the
whole IO pool descheduled the main thread hundreds of times and froze
navigation for over a second.
The image loader now caps the request dispatcher at 2 parallel ops and
the decode/transformation pools at 2/1: images still fill in steadily
while scrolling but can no longer eat every core at once. Combined with
the release build on the TV (debug's JIT bursts produced 900 ms+ frames
by themselves), the same navigation settles at p90 ~13 ms per frame
with a worst frame of ~180 ms when a new row composes.
Jeena
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