muh
50c731412a
[INSIGHT] tuning_scan: gridDim.x < 500 makes ALL delay policies equivalent on BI-V100
From single_pass_scan_operators.cuh detail::delay():
if (gridDim.x < GridThreshold=500) → __threadfence_block()
else → __nanosleep(Delay)
BI-V100 max gridDim.x ≈ 80 (16 SMs × 5 subscription). Always < 500.
Therefore ns/dcid/l2w tuning dimensions are irrelevant — every delay
constructor degrades to threadfence_block on this hardware.
Also: paged_attn.py spread_out_items_per_thread adaptive tile sizing.
CCCL source: single_pass_scan_operators.cuh lines 160-175.