Function fp8_gemv_rowscale_batch8_rt2 

pub fn fp8_gemv_rowscale_batch8_rt2(
    gpu: &dyn GpuBackend,
    kernel: KernelHandle,
    input: DevicePtr,
    weight: &Fp8DenseWeight,
    output: DevicePtr,
    m: u32,
    n: u32,
    k: u32,
    stream: u64,
) -> Result<()>

2026-09-25: Register-tiled row-scaled FP8 GEMV for up to 8 rows, two outputs per 64-lane group (kernel fp8_gemv_rowscale_batch8_rt2, module fp8_gemv_rt). input [M, K] BF16, output [M, N] BF16; the kernel applies row_scale[n] at write-out. The DFlash drafter’s FP8 path calls it (dflash_head/forward_block.rs). Refuses m outside 1..=8 and a k that is not a multiple of 16.