ad45873a1b
Priority aging in xenia-cpu/scheduler.rs:pick_runnable
(effective_priority = base + age_bonus(now_round - last_run_round),
capped at +31, AGING_ROUNDS_PER_BONUS=1). Strict-priority was parking
priority=0 threads behind CPU-bound priority=15 audio mixer
(sub_824D1328 guest spinwait at PC=0x824d1404 on CPU5). Aging
eventually picks the starved thread, breaking the producer-consumer
cycle that caused 5-tid wedge at PC=0x824ac578 since AUDIT-049 (10 May).
Cascade observed: tid=13 clean exit; events 121K -> 13M (107x); last
host_ns 767ms -> 51,011ms (66x); 8 new threads spawn; VdSwap 1 -> 2.
Complete two-day iterate sequence (2026-05-27 -> 2026-05-28):
- 2.F: VdSwap drain timeout 900ms -> 1ms (xenia-gpu/handle.rs); 876x
perf win on VdSwap kernel callback
- 2.H: vA0000000 physical heap bucket added (state.rs, exports.rs);
ctx_ptrs now in 0xA0000000-0xBFFFFFFF range matching canary
- 2.L: Phase-A diff harness categorized [return_value mismatch],
[status mismatch], [args_resolved.path mismatch] tags
(tools/diff-events/diff_events.py); closes reading-error #41
(silent test-harness state leak invalidating trace diffs)
- 2.M: always-on exit-thread-state.json sibling to Phase-A JSONL
(event_log.rs + xenia-app/main.rs); closes reading-error #42
(Phase-A blind to blocked-forever waits)
- 2.Q: signal.match kernel instrumentation in NtSetEvent /
NtReleaseSemaphore / KeSetEvent / KeReleaseSemaphore
(exports.rs); emits target_handle + waiter_count + waiter_tids
- 2.T: wake.requested kernel instrumentation in wake_eligible_waiters
(exports.rs); emits target_tid + transition + new_state
- 2.V: scheduler priority aging (xenia-cpu/scheduler.rs) [keystone]
Plus accumulated WIP from earlier May (contention_manifest,
phase_b_snapshot, xam/xaudio enhancements, analysis db, xex loader,
xenia-app main loop, etc.). Audit-runs/ artifacts remain untracked
per project convention.
Tests: 300 xenia-cpu / 227 xenia-kernel / 5 xenia-app / 19 xenia-path
/ 30+ smaller suites -- all PASS, 0 regressions. Determinism preserved
(2x cold runs bit-identical at 13,003,881 events post-2.V).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
60 lines
3.7 KiB
Markdown
60 lines
3.7 KiB
Markdown
---
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address: 0x8245FEB8
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classification: normal_callee
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confidence: high
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last_audit: 060
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aliases:
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- "vptr installer for dispatch_table 0x820B5830"
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- "AUDIT-059 'dead' (FALSIFIED)"
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---
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# sub_8245FEB8 — vptr installer for dispatch_table 0x820B5830
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## Synopsis
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Installs a vtable pointer / dispatch-table entry into a runtime-allocated object. Body contains `stw r11, 0(r31)` at `0x8245FFC0` writing the vtable address to the object's slot 0. After install, the object's `bctrl` dispatch reaches the methods in `dispatch_table @ 0x820B5830` (slot 0 = `sub_8245F1D0`, slot 1 = `sub_8245EC10`). Fires 5× in ours / 2× in canary; lives in the AUDIT-050 worker cluster but is NOT dead in either engine — both engines reach the same call site `sub_824601A0+0x68 (PC=0x82460208)`.
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## Evidence
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- Body opcode at `0x8245FFC0`: `stw r11, 0(r31)` — vtable install pattern.
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- Two static callers per `xrefs` table (`source_func`):
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- `sub_824601A0` at `+0x68` (PC `0x82460208`) — 1 site
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- `sub_8245FB68` at `+0x198` and `+0x1C0` (PCs `0x8245FD00` and `0x8245FD28`) — 2 sites
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- AUDIT-060 Probe C-Win Windows Debug canary: `--log_lr_on_pc=0x8245FEB8`, 120s → **2 fires, both lr=0x8246020C** (= `sub_824601A0+0x6C`, post-bl PC). `r3=BC365C40` (same object), `r4=4` then `r4=1` (different slot indices), `r31=701CF2E0` then `r31=705AFAA0` (different threads).
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- AUDIT-060 Probe O ours: `--ctor-probe=0x8245FEB8 -n 500M` → **5 fires total**: 1 from tid=1 boot path at cycle 5.5M via `sub_824601A0+0x68`, 3 more from tid=1 during UI inflation, 1 on tid=13 at cycle 23788 via the wedge chain.
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- The `r4` parameter (slot index) and the `r31` saved value diverge per call; install target object differs.
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## Activation
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Direct `bl` from one of:
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- `sub_824601A0+0x68` (most frequent — boot path)
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- `sub_8245FB68+0x198` and `+0x1C0` (internal lib path, sub_8245FB68 itself has callers `sub_8245F880`, `sub_8245FAB0`)
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Caller chain upward: `sub_824601A0 ← sub_82460118 ← sub_82452AB8 ← sub_82452DC0`. The vptr-install path piggybacks on the work-submitter cluster.
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## Static graph
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- Callers: `sub_824601A0`, `sub_8245FB68`.
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- Body: vtable write at `+0x108` (`0x8245FFC0`). Other body content not yet detailed.
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- The vtable being installed is implicit in caller-supplied `r11` (and possibly elsewhere).
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## Audit log
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- **AUDIT-060 (2026-05-12)** — measured 5× ours, 2× canary, identical call site both engines. AUDIT-059's framing falsified. Convergence to AUDIT-050 work-submitter cluster confirmed. [confirmed]
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- **AUDIT-059 (2026-05-11)** — claimed as "vptr installer dead in ours" because static graph showed `sub_8245EC10` (slot 1 of the installed dispatch table) had 0 static callers reachable from any caller-chain that DB classified as live. [STATUS: falsified by AUDIT-060 — was alive in ours all along; the DB caller-chain reachability call was too narrow.]
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## Open questions
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- What is the *class* being installed? (Read `r11` at the `stw r11, 0(r31)` site — canary trace shows it's a specific dispatch table.)
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- The 5 ours fires vs 2 canary fires — is this a parity match (canary just had only 2 because of the same AUDIT-056 3.21× upstream gate) or does ours over-fire? Aligning instruction-horizon vs wallclock would clarify.
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- Slot-1 method `sub_8245EC10` is named the canary signaler B. It fires 2× in ours per AUDIT-060 — but not on the wedge handle (per AUDIT-059 ours signal_attempts=0 on 0x12AC). What handle is it signaling in ours?
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## Cross-references
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- Installs dispatch_table at: `0x820B5830`
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- Slot 0: `sub_8245F1D0` (referenced; not yet dossierd)
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- Slot 1: [sub_8245EC10](sub_8245EC10.md)
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- Direct callers: `sub_824601A0`, `sub_8245FB68`
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- Audits: 059, 060
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- Artifacts: `audit-runs/audit-059-gamma-wedge/`, `audit-runs/audit-060-fnptr-array-bootstrap/`
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