Option B fold: the lrab math previously in
``_gqa_attention_decode_long.py`` (used only as a thin re-export by
the Case 4 wrapper and as the import source for ``_merge_running``
in Cases 1 / 3) now lives inline in the Case 4 kernel file. ``sub_w``
is hardcoded to 4 (the 4×2 cube sub-mesh geometry; root cube 6);
the legacy ``sub_w=0`` 1D-chain backward-compat path is removed
along with its dedicated tests — the dropped ``single_user_*`` /
``multi_user_*`` panels that exercised it are already gone.
Production changes:
- inline lrab math into _gqa_attention_decode_long_ctx_cube_sp_pe_sp.py
(drops sub_w param; _ROOT_CUBE=6 baked in)
- inline _merge_running into Cases 1 (cube_sp_pe_tp) and 3
(cube_repl_pe_sp) so they no longer depend on the deleted file
- delete src/kernbench/benches/_gqa_attention_decode_long.py
- remove dead _run_decode_panel / _DECODE_* constants /
decode-side _PANEL_DISPATCH / _make_bench_fn decode branch
from milestone_gqa_headline.py (only the prefill panel remains)
- update _gqa_attention_decode_opt2.py docstring reference
Test changes:
- delete 7 legacy test_gqa_*.py files that pre-dated the 4-cases
architectural split (coverage now subsumed by the 16 4-cases tests)
- remove test_opt2_matches_opt3_data_mode + _run_decode_data helper
from test_gqa_decode_opt2.py (the parity check required sub_w=0
which no longer exists; opt2's other 4 tests preserved)
20/20 tests pass (16 4-cases + 4 opt2 smoke/dispatch).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
mukesh
756680f4e6