fix(stall): T2 amplification kill — resume-edge pacing + ABR starved-window guard #53

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enricobuehler merged 3 commits from worktree-stall-ride-through into main 2026-08-05 06:35:32 +00:00

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3 Commits

Author	SHA1	Message	Date
enricobuehler	1d6f4760f3	Merge branch 'main' into worktree-stall-ride-through	2026-08-05 06:22:41 +00:00
enricobuehler	e5ca213339	fix(core/abr): a starved window is never a decode-knee sample ... Stall program T2 (amplification kill), the phantom-latch half. A deciding window that delivered under a quarter of the target rate (a host-side capture stall, an outage, a mid-window pause) carries starvation-shaped distress — a jump-to-live flush, a keyframe-ask burst — that the decode-cap latch read as decoder evidence: under a periodic capture stall (the RDNA4 standby-sink field cases, one stall every ~5 s) every edge offers another 'backoff' at the SAME rate, and one pair latches a phantom decoder knee at whatever rate the display driver happened to interrupt. The session then fights the cap's re-probe ladder (+12.5% per 16-128 clean windows) for minutes on a decoder that was never the problem. Starved windows still back off (real damage deserves the safe response) but take the same 'not a knee sample either way' arm as a draining backoff: they neither latch a decode cap nor erase the reference a genuine choke set, so a real knee's pair still finds itself around the interruption. The ¼ bar sits deliberately far under the ×¾ utilization bar climbs require. Gates: 44 abr tests green (2 new: the stall-cycle no-latch scenario and the reference-preservation scenario), full core lib suite 346 green (--features quic), fmt + clippy clean.	2026-08-05 00:28:25 +02:00
enricobuehler	e5416646f9	fix(host/send): a stall-resume frame paces at the proven rate instead of blasting ... Stall program T2 (amplification kill), the resume-burst half. The native pace budget was min(0.9 × time-to-deadline, overflow at ~3× stream rate) — for steady-state frames the rate term is smaller and decides, but for an OVERSIZED frame (a capture-stall resume carrying seconds of scene delta, a cold IDR) the deadline term clamped a multi-interval overflow into the remainder of ONE: an instantaneous many-×-stream-rate blast that overruns the socket tx-buffer and loses the very frame that would have ended the freeze. Field fingerprint across three RDNA4 standby-sink cases: WSAENOBUFS(10055) + loss_ppm spikes at stall edges, then a recovery-IDR round trip per retry while the client shows 'current bitrate 0.1'. The budget is now the overflow's wire time at the pace rate itself (send_pacing::native_budget, pure + unit-tested), bounded by an absolute 100 ms ceiling so a pathological frame can't park the send thread; the deadline stays a target, never a license to blast. Steady-state frames produce byte-identical schedules (the rate term already decided); PUNKTFUNK_PACE_FACTOR=0 keeps the legacy deadline-only spread; the GameStream plane's Moonlight-pinned schedule is untouched. Gates: host clippy --all-targets -D warnings + 9 send_pacing tests green (linux/amd64 container), fmt clean.	2026-08-05 00:28:13 +02:00