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>
diff-state
Phase B initial-state snapshot diff tool. Stdlib-only Python. Mirrors the
shape of tools/diff-events/ but operates on the static structural
snapshots emitted by phase_b_snapshot at the moment immediately before
the first guest PPC instruction of the XEX entry_point executes.
Usage
python3 tools/diff-state/diff_state.py \
--canary <snapshot_dir>/canary \
--ours <snapshot_dir>/ours \
--out <snapshot_dir>/report.md
Writes:
<snapshot_dir>/report.md— human-readable divergence catalog<snapshot_dir>/report.json— machine-readable sibling (same content)
Exit codes
| code | meaning |
|---|---|
| 0 | no divergence (or --validate-identical succeeded) |
| 1 | divergences found |
| 2 | STOP triggered (image_loaded_sha256 / xex_entry_point / iso_sha256 mismatch) |
Field-comparison rules
Lives at the top of diff_state.py as Python constants — read those for
the authoritative spec. Summary:
engine,schema_version,deterministic_skipare always skipped.cpu_state.json: skiphw_id.kernel.json: skipraw_handle_id,exports_registered_count.config.json: skipbuild_id,iso_path,host_ns_at_snapshot,wall_clock_iso8601,cli_argv,cvars.phase_b_snapshot_dir.- Each snapshot's
deterministic_skiparray is honored too.
Set vs sequence semantics
- Set (sort by key, then positional compare):
kernel.json::objects(key=handle_semantic_id)kernel.json::handle_name_table(key=name)vfs.json::cache_root_listing(key=relpath)memory.json::heaps(key=base)
- Sequence (positional compare): everything else, including
memory.json::regions(which both engines emit pre-sorted by(start, end)).
Classification
| class | trigger | priority |
|---|---|---|
| σ-structural | field missing/extra; sequence-length mismatch; set element only in one engine | 1 (always report) |
| δ-content-STOP | image_loaded_sha256 / xex_entry_point / iso_sha256 mismatch |
STOP (exit 2) |
| δ-content | other *_sha256 field differs |
2 |
| γ-kernel-content | objects[].details field differs |
2 — primary Phase C target |
| κ-cache | non-empty cache_root_listing either side |
re-run after rm -rf of caches |
| ε-host-allocator | heap base/region start differs but sha256 agrees | catalog only |
| τ-host-timing | deterministic_skip-listed timing field |
silent unless verbose |
Negative-test recipe
To verify the tool catches a hand-mutation:
cp -r snap-001/ours snap-001/ours-mut
sed -i 's/"thread_id": 1/"thread_id": 999/' snap-001/ours-mut/kernel.json
python3 tools/diff-state/diff_state.py \
--canary snap-001/ours --ours snap-001/ours-mut --out /tmp/r.md
# exit code 1; report names objects[handle_semantic_id=...] details.thread_id