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Native-path seek landing time grows ~4x between 6.6.0 and 6.7.0 (median 0.26-0.36 s -> 1.2 s); software path unaffected #305

Description

@rrgomes

Summary. Seek-to-landed time on the native (loopback-HLS) path grew from a ~0.3 s median to ~1.2 s across the 6.6.0 → 6.7.0 window — same box, same titles, same scrub pattern. Software-path seeks are unchanged. A same-day, same-box pin-back A/B reproduces it: engine 6.6.0 lands a median 0.36 s, 6.7.0 a median 1.22 s.

Numbers (host seek instrumentation, seek-issued → engine-landed, direct-URL sources on a LAN PMS, 3rd-gen Apple TV 4K):

title / path era n median max
4K HEVC DV-P7 (native) 6.5.6/6.6.0 multi-day baseline 24 0.26 s 1.97 s
same 6.7.0 34 1.22 s 8.30 s
same, same-box same-day A/B pinned 6.6.0 30 0.36 s 5.42 s
4K HEVC no-DV (native) baseline 36 0.14 s 0.44 s
same 6.7.0 36 0.40 s 0.90 s
SD MPEG-2 (software) both eras ~0.11 s unchanged
1080p AV1 (software) both eras ~0.08 s unchanged

Producer restarts stay fast throughout (8–34 ms in the logs); the added time sits between the restart and the landing.

Scope notes. The multi-second outliers appear on BOTH pins in the same-day A/B and are fatter than the multi-day baseline's, so we are not attributing the tail to this window — it looks scrub-pattern-dependent (bursts of coalesced presses) and may be its own story. The claim here is the median shift, which the pin-back isolates cleanly.

Suspect. The only change we can see on this path in the window is the range-boundary rework (the detour-fill fix — which works; the stutter it fixed is gone and we just closed that issue). A seek is a reposition, and a native-path landing involves several sequential reads (producer restart, segment rebuild, player re-buffer), so a small per-reposition cost would be paid several times per seek while staying under the software path's noise floor. That's inference, not measurement — happy to run an instrumented build or capture whatever timing you'd want around startPersistentConnection on a seek.

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