Wires the q_drift_rate_ema kernel + ISV slot Q_DRIFT_RATE_INDEX=129
(landed in fc8dbb0a8) into the production training path:
- StateResetRegistry FoldReset entry isv_q_drift_rate -> 0.0
(companion to A.1's prev_epoch_q_mean reset; both ensure no
cross-fold leakage of drift state).
- reset_named_state dispatch arm in training_loop.rs.
- Per-epoch launch_q_drift_rate_ema call after the Q-drift kill
check, gated on the same `prev_epoch_q_mean.abs() > 1e-6`
cold-start guard. Both q_mean_curr and q_mean_prev are in scope
BEFORE the `prev_epoch_q_mean = q_mean` update, so the producer
sees the correct delta.
- tau_update_kernel.cu multiplies the cosine-scheduled,
health-coupled tau_eff by `1 / (1 + clip(ISV[129], 0, 4))` so
tau ranges [tau_base/5, tau_base] — monotone dampening under
drift; healthy runs (drift ≈ 0) unaffected.
- reset_for_fold comment in trainer/mod.rs notes the registry
entry handles the new ISV slot.
Predicted impact: Plan C fold 0 ep2 with q_mean(t)=0.82,
q_mean(t-1)=-0.018, ISV[16]+ISV[21]≈0.1 -> drift_rate ≈ 8.4 ->
clipped to 4 -> tau_eff = tau_base × 0.2 (5× slower target sync,
dampens Q-target optimism through the inflation spike).
a52d99613 fold 0 with q_mean staying ~0.21 -> drift_rate ≈ 0 ->
tau_eff = tau_base (unchanged).
Per pearl_adaptive_moe_lambda.md — canonical "EMA-tracked
diagnostic drives a controller" pattern. Per
pearl_cold_path_no_exception_to_gpu_drives.md — cold-path scalar
arithmetic stays on GPU. Per feedback_no_partial_refactor.md —
consumer (tau_update + state_reset + producer launch) all migrate
together in this commit.
Layout fingerprint already shifted by fc8dbb0a8 (slot + ISV_TOTAL_DIM
bump); no additional fingerprint shift in this commit.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
b4d4a8d046