import itertools



def build_chunked_prefill_configs():
    """Autotune configs for chunked prefill unified kernel.

    Note: The autotune key is
    ["NUM_GROUPS", "HEAD_DIM", "PAGE_SIZE", "DLLM_BLOCK_SIZE", "IS_BLOCK_CAUSAL", "IS_PREFIX_FULL"],
    so configs are selected based on those runtime parameters.
    """
    BLOCK_M_LIST = [64, 128]
    BLOCK_N_LIST = [64, 128]
    NUM_STAGES_LIST = [1, 2, 3]
    NUM_WARPS_LIST = [4, 8]

    CONFIGS = list(
        itertools.product(
            BLOCK_M_LIST,
            BLOCK_N_LIST,
            NUM_STAGES_LIST,
            NUM_WARPS_LIST,
        )
    )

    return [
        {
            "BLOCK_M": c[0],
            "BLOCK_N": c[1],
            "num_stages": c[2],
            "num_warps": c[3],
        }
        for c in CONFIGS
    ]