Replace the out=128 / scale=0.5 ablation substrate with a paper-faithful one:
- Use the trace's real output_length (drop completion_tokens_override=128). The
0-8k chat window has p50=531 / p99=2436 / max=35168 output tokens, so decode
(TPOT) becomes the dominant bottleneck instead of an artificial 128-token cap.
- replay_time_scale=0.8775, chosen by criterion-A: binary-search the smallest
scale whose A-family L-C-A similarity to the real (scale=1.0) arrivals stays
>= tau (0.90). The old scale=0.5 had sim_A=0.56, distorting the arrival axis
far below the tau bar used everywhere else. New calibrator:
scripts/calibrate_time_scale.py.
- Per-probe Stop-A-consistent drain deadline (worker._probe_drain_deadline): the
wall-clock a *feasible* config needs to drain the LCA-admitted set
(last_arrival + worst-case TTFT + p99_out * TPOT budget + margin). With real
outputs decode dominates wall-clock, so the old fixed 320s cap would truncate
the Stop-A offered window mid-decode. early_stop_max_elapsed_s (1000s) is now a
hard ceiling; the per-probe deadline governs. The lag cap still cuts overload.
12-iter paired driver (both arms on dash1, removes the dash0/dash1 host confound):
scripts/run_ablation_pair_d1.sh. 115 tests pass.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
scale=0.2 made TP1 uniformly infeasible (no baseline); bound decode to 128 tokens and
use mild 2x compression so TP1 registers a real, fast baseline, with 6 probes to span
TP1's low and TP4's high feasibility boundaries. Both configs identical except use_harness.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
First TP1 baseline probe under scale=0.2 ran ~6min (severe overload, 260
preemptions on the lighter half of the trace; TP1 is decode-bound and the
arrival-lag early-stop does not cut a decode-drain-bound probe). Cut
search.max_probes 5->3 to bound binary-search steps per trial. Caps stay
at elapsed=180/lag=30. Both configs still differ only in use_harness +
study_id.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
At replay_time_scale=0.2 the 600s arrival window compresses to 120s, so
the inherited 900s wall-clock elapsed cap let overloaded TP1 probes burn
~15min each (the tractability hazard the brief flagged). Scale the caps
proportionately to the time axis: early_stop_max_elapsed_s 900->180,
early_stop_max_lag_s 120->30. Feasible probes (~120s arrival + drain)
finish well inside 180s; overloaded probes die in ~3min. Both configs
still differ only in use_harness + study_id. Adds the ablation doc
skeleton and a read-only trajectory-extraction helper.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Two configs identical except llm.use_harness and study_id, for the
controlled harness-ON vs naive-OFF tuning-trajectory ablation on dense
Qwen3.5-27B. Faster substrate (replay_time_scale=0.2, search.high=0.25,
max_probes=5) keeps the ablation tractable; Stop-A stays enabled.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The wide 0.5 range made TP1 (low-capacity) waste many infeasible high-theta probes,
and the 900s request timeout made overloaded probes drain hung requests for 15min
each. Cap drain at 180s and bound the search to where the boundaries actually are.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
A single-config baseline run with adaptive_stop disabled and replay_time_scale=1.0,
so per-request probe_details capture the full 600s window for offline analysis of
whether truncating at the L-C-A convergence prefix preserves the feasibility verdict.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
