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vllm.models.kimi_k3.amd.kda_metadata

ROCm Kimi-K3 specialization of GDN attention metadata.

The request classification and cudagraph staging intentionally mirror GDNAttentionMetadataBuilder. Only the FLA chunk metadata is built differently on device rather than on the host.

Functions:

prepare_chunk_metadata_device(cu_seqlens, cu_seqlens_cpu, chunk_size)

Build FLA chunk metadata on device, with no host<->device transfer.

Source code in vllm/models/kimi_k3/amd/kda_metadata.py 
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def prepare_chunk_metadata_device(
    cu_seqlens: torch.Tensor,
    cu_seqlens_cpu: torch.Tensor,
    chunk_size: int,
) -> tuple[torch.Tensor, torch.Tensor]:
    """Build FLA chunk metadata on device, with no host<->device transfer."""
    num_seqs = cu_seqlens_cpu.numel() - 1
    seq_lens = cu_seqlens_cpu[1:] - cu_seqlens_cpu[:-1]
    num_chunks = int(((seq_lens + chunk_size - 1) // chunk_size).sum())

    chunk_indices = torch.empty(
        num_chunks, 2, dtype=cu_seqlens.dtype, device=cu_seqlens.device
    )
    chunk_offsets = torch.empty(
        num_seqs + 1, dtype=torch.int64, device=cu_seqlens.device
    )
    _chunk_metadata_kernel[(num_seqs,)](
        cu_seqlens,
        chunk_indices,
        chunk_offsets,
        num_seqs,
        BT=chunk_size,
        BLOCK_N=max(_MIN_BLOCK_N, next_power_of_2(num_seqs + 1)),
        BLOCK_T=_BLOCK_T,
        num_warps=4,
    )
    return chunk_indices, chunk_offsets