Function topk_tile 

pub fn topk_tile() -> usize

2026-09-25: Tile width dsa_topk_pools walks the pool axis in.

The block holds two tiles, the running best list and the candidate tile, of [f32, i32] pairs: 16 · T bytes. This is the largest power of two T that fits TOPK_SMEM_CEILING: 2,048.

Glm5NextDsaLayer::decode_k passes this value to dsa_write_geom as tile; the kernel has no copy of it.