Function f32_gemv_kernel_on 

pub fn f32_gemv_kernel_on() -> bool

MEMRA_F32_GEMV_KERNEL=1 (lane/f32-gemv-rows-20260905, default OFF pending its model-scale row): the f32-resident linear at the decode/verify tier (m <= 16) takes the native gemv_f32_rows kernel (one block per (row, token), fixed reduction tree) instead of cuBLASLt, whose m=1 path is a dot_kernel + reduce_1Block_kernel PAIR: two launches and ~9 us of host latency each, 33 pairs per token on the eager MLA layers (the DSA indexer’s wk, kpool_gate, weights_proj). NUMERIC CLASS (cuBLAS’s split is its own): tolerance + determinism + m-identity gate tests/f32_gemv_rows_gpu.rs. Shapes that do not fit (in_f % 1024 != 0, out_f > 65535, m > 16) keep cuBLASLt. Read per call.