Replication of the
qlabs-eng/slowrun unlimited-compute-track
submission (
unlimited/train.py @ commit
4681cfd): eight ~2.7B-param GPT models
(30 layers, d_model 1792, 14 heads, SwiGLU, rotary + QK-norm, x0-projection value
embeddings, sliding-window attention SSSL, Muon+AdamW, dropout 0.1, weight decay 1.6),
each trained 12 epochs on the same fixed 100M-token FineWeb corpus (GPT-2 tokenizer,
SHA-256-pinned), differing only in seed. Final metric: logit-averaged ensemble val loss.
Prior leaderboard record: 3.264. Individual models: val loss 3.333–3.339.
Trained on PSC Bridges-2 (8× separate 1-GPU H100 jobs — mathematically equivalent
to the documented 8-GPU launch since the total batch of 524,288 tokens and the
seeded shuffle-to-step mapping are GPU-count-invariant). Two environment deviations
from the original script, both required on RHEL 8 / glibc 2.28: FA3 kernel from
kernels-community/flash-attn3 (same upstream source as the hardcoded
varunneal/flash-attention-3, which needs glibc >= 2.34) with the attention shim
excluded from torch.compile tracing via torch.compiler.disable.
Data: FineWeb sample-10BT, 100M train / 10M val tokens, byte-identical to the
repo's pinned SHA-256 hashes.