ef93a4fa14
Source changes (dormant parity infra, retained from iterate 2.AI/2.AO): - xenia-kernel/exports.rs: nt_create_event manual_reset polarity + related event wiring - xenia-gpu/mmio_region.rs: D1MODE_VBLANK_VLINE_STATUS hardcode parity Also lands the audit-runs/ analysis notes (.md/.txt/.json digests) for the iterate 2.x VSync/0x10e8/0x1004 wedge investigation. Raw trace dumps (.jsonl/.gz/.csv/.stdout) and agent worktrees (.claude/) are gitignored as regenerable local artifacts — see memory + HANDOFF for the running findings. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
96 lines
4.4 KiB
Markdown
96 lines
4.4 KiB
Markdown
# Phase C+22 cold-vs-cold result (2026-05-18)
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## Outcome: NO engine change. ESCALATE.
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Verified C+21 absorber engaged correctly on the fresh cold-vs-cold
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measurement; main matched-prefix is stable at **104,607**
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(no change from C+21 baseline). Divergence at canary idx 104,610
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(post-absorb) vs ours idx 104,607 classified as **(A) ours
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fast-paths while canary contends → state mutated during the wait
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→ different post-acquire branch**. Same root cause as C+20.
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## Matched-prefix table (vs C+21 baseline)
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| chain | C+21 | C+22 (fresh c22) | delta |
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|--------------------------------|---------|------------------|-------|
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| canary tid=6 → ours tid=1 main | 104,607 | **104,607** | 0 |
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| canary tid=4 → ours tid=11 | 11 | 11 | 0 |
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| canary tid=7 → ours tid=2 | 32 | 32 | 0 |
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| canary tid=12 → ours tid=7 | 3 | 3 | 0 |
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| canary tid=14 → ours tid=9 | 41 | 41 | 0 |
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| canary tid=15 → ours tid=10 | 16 | 16 | 0 |
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## Floating-event absorption counts (fresh c22)
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| chain | floating_create (c/o) | floating_wait (c/o) |
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|--------------------------------|-----------------------|---------------------|
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| canary tid=6 → ours tid=1 main | 1 / 0 | 2 / 0 |
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| canary tid=15 → ours tid=10 | 0 / 1 | 0 / 0 |
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| others | 0 / 0 | 0 / 0 |
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C+18 absorber engaged on main chain (1 canary handle.create
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floated) and on tid=15→10 (1 ours handle.create floated).
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C+21 absorber engaged on main chain (2 canary wait.begin events
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floated — the contention slow-path emitted them in this run).
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## Cold-stable invariants
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- **ours-cold byte-identical to C+19 archive**: 121,569 events
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match post-normalization (host_ns/guest_cycle excluded).
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Reading-error class #34 (cold-run determinism depends on input
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path form) discovered + documented; ALL future cold runs must
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use `.iso` not `.xex`.
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- **Phase B image hash**: `ea8d160e9369328a5b922258a92113efb8d7
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ce3e1a5c12cc521e375985c91c18` — unchanged (no engine source
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change).
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- **Engine source**: UNCHANGED in both ours and canary. No new
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exports, no new flags, no diff-tool changes.
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## Verification of NOT-jitter
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Pattern in canary's tid=6 post-loop region (idx 104,604-104,615
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`import.call` events only):
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| sample | events |
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|------------------|--------------------------------------------------------------|
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| c21 archived | E E L L |
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| canary jitter-1 | E (wait.begin slow path) E L L |
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| canary jitter-2 | E E L L |
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| canary jitter-3 | (shifted) E E L L |
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| fresh c22 | E (wait.begin slow path) E L L |
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All canary samples take the EXTRA nested RtlEnter after the
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post-loop `E` at 104,604. Ours never does — it goes `E L NtClose`.
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This is a real guest-code branch divergence, NOT diff-tool jitter.
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## Cascade outcome
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- A=verify divergence is NOT jitter: PASS
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- B=classify (A/B/C/D): PASS — **(A) scheduler-determinism +
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post-wait state-mutation effect**
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- C=land fix or escalate cleanly: ESCALATION (per prompt
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authorized fallback)
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- D=main matched-prefix > 104,607: N/A (no engine change)
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## Files
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- `investigation.md` — detailed framing, mechanism, rejected
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fixes, reading-error #34 documentation, next-targets.
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- `diff-cold-vs-cold.md` — full Phase A diff report (fresh c22
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cold-vs-cold).
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- `canary-binary-cache-pre-wipe.tar.gz` — pre-wipe canary
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binary-dir cache backup (restored post-run).
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- `canary-xdg-cache-pre-wipe.tar.gz` — pre-wipe canary XDG
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cache backup (restored post-run).
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- `ours-cold-stdout.log` / `canary-cold-stdout.log` — run logs.
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## Next-target recommendation
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**C+23 = D-NEW-2** (`KeWaitForSingleObject` `timeout_ns`
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sign/scale asymmetry on canary tid=12 → ours tid=7 idx=3):
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canary=-30000000 vs ours=429466729600. Independent of
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scheduler-determinism. Out of scope for C+22 per the C+22
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prompt's explicit "You may NOT ... Fix D-NEW-2 in this
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session." Likely ~20-40 LOC in `ke_wait_for_single_object`'s
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timeout-pointer dereference.
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