Phase 2 (L34, L35). Both findings' line citations were accurate this time.
- L34 data race: process() (Rack's audio thread) called
imlShadow.get_example_features()/get_example_labels() directly on the WORKER
thread's private engine — which the file's own THREADING INVARIANT comment
says only the worker may touch — while workerLoop() concurrently
clear/refills those same std::vector<std::vector<float>> members via
load_examples(), train_(), randomise_weights and clear_dataset. Unsynchronised
reader/writer on a non-atomic vector: undefined behaviour.
Fix extends the staged handoff the file ALREADY uses for pendingWeights
rather than adding a second mutex: the worker deep-copies features/labels
into pendingFeatures/pendingLabels at the same instant it copies
pendingWeights, immediately before weightsPending.store(true), and the flag is
now released only after the whole batch is consumed — closing an early-release
window the old code had. process() no longer references imlShadow at all
(verified: the only surviving mention is a comment).
- L35: process() ran full jansson serialize on every weight-swap OSC push and
full json_loads + dataFromJson on incoming OSC state — heap-heavy tree work
on the audio thread. The plan said to move it to the worker. It is DELETED
instead: reading the actual transport shows both directions talk to nobody —
osc-client.ts only ever sends {params|input|feedback}, and bridge.ts has no
state/weights case and explicitly drops other addresses. Relocating
heap-heavy work to serve a confirmed-zero consumer is complexity without a
requirement; removing the cause is the smaller coherent design.
dataToJson/dataFromJson are UNTOUCHED — they remain the live consumers for
Rack patch save/load and the .nisps preset menu, both off the audio thread.
Neither is empirically reproduced: a real race needs a live Rack engine under
TSan, which is not available here. Justified by reading, and verified by
`cd vcv && make -j4` (clean) plus the host suite including
test_vcv_iml_parity.cpp, which pins iml.hpp bit-exactly against the core MLP —
iml.hpp was not modified, and parity holds.
Known remaining, pre-existing and out of scope: process() still takes a brief
lock_guard on feedbackMutex to copy a small staged struct, and several config
fields (slewMs, oscPort, output/input range flags) are written by the UI thread
without atomics.
Phase 1 group 7 (L33). vcv/test/smoke_test.cpp included a header that no longer
exists (a retired nisps-core path), asserted the pre-P6 2x12 module shape, and
ran in no gate; a compiled smoke_test binary was tracked alongside it. Removed
the directory plus Makefile.dist, updated BUILDING.md's two references, and
deleted the unreachable reply-to-sender branch in osc_server.hpp.
Gates: run-all-tests.sh ALL GREEN.
Replace the vendored runtime MLP in vcv/src/iml.hpp (DetRng + 3D-weight-store
MLP + Dataset + IML) with a THIN, Rack-free adapter over the shared core:
nisps::ml::MLPCore<nisps::ml::DynamicStorage> (8->[16,24,16]->16, the P2 dynamic
case), nisps::Rng, and the core MLP's own FIFO dataset. Behaviour changes from
the vendored approximation to core-exact firmware/WASM semantics.
- MEMLNaut.cpp: staged/pending weight buffers and patch JSON now use the core's
flat [weights..][biases..] vector (nisps::IML<float>::Weights); patch version
bumped to 3. Double-buffer / single-writer threading discipline unchanged.
- New ctest tests/cpp/test_vcv_iml_parity.cpp: seeded train/infer/move_weights
session through the adapter is memcmp-equal to a bare MLPCore<DynamicStorage>.
- Docs: vcv-module.md delta #5 marked CLOSED (2026-07-18); MAP.md vcv/ updated.
Closes vcv-module.md delta #5.
8 inputs x 16 outputs; per-output LED ring widget (drawLayer+nvgArc); palette
from frontend tokens; OSC bridge verbs for bidirectional browser training;
vendored self-contained iml.hpp (retired nisps-core); compiles against Rack
SDK 2.6.4. See SPEC.md BUILD DELTAS.
Fixes from Opus 4.6 review (C1-C6, I1, I3, I4, I8):
C1: static lastOutputs → per-instance lastOutputsForDelta member
C2: add_example() now on audio thread only (owns iml); worker reads
from mutex-protected staging area (stagedFeatures/stagedLabels)
C3: Worker reads stagedWeightsForWorker (not iml.get_weights()),
eliminating concurrent read/write on iml's MLP
C4: Worker spins on weightsPending before writing pendingWeights,
preventing double-write race
C5: RAND and CLEAR now enqueue Randomize/Clear jobs through worker
instead of directly mutating iml on the audio thread
C6: OSC callbacks stage JSON into oscStagedJson + atomic flag;
audio thread applies in process() (no recv-thread mutation)
Also fixed:
- I4: Separate pendingJob field (enqueueJob no longer overwrites currentJob)
- I8: Removed redundant swapReady atomic
- noiseLevel, cachedNovelty, cachedConfidence now std::atomic<float>
- Worker syncs examples back to iml after training via load_examples()
Replace direct-mutation threading with shadow IML:
- Background thread clones weights from main → shadow IML
- Training and perturbation operate only on shadow instance
- New weights staged in pendingWeights, swapped atomically by audio thread
- Thumbs-down now enqueues Perturb job instead of calling move_weights directly
- Audio thread applies new weights via iml.set_weights() at safe point
- Examples copied to shadow for training, results copied back as weights only
Threading invariant now fully enforced: background thread never writes to
the inference IML. Audio thread applies staged weights between inference calls.
