The data preload created a dummy DQNTrainer with buffer_size=1, which
fails the GPU PER capacity check (capacity must be >= batch_size).
This caused the preload to fail silently, falling back to per-trial
data loading from disk — 50 × 5s = 250s wasted.
Fix: set buffer_size = max(batch_size, 1024) so the PER allocation
succeeds. The preload trainer doesn't train — it just loads data into
a shared Arc for all trials.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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