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vllm.platforms.xpu

Classes:

Functions:

  • get_mem_info_wrapper

    Get memory info for a device, compatible with torch.accelerator.get_memory_info API.

XPUPlatform

Bases: Platform

Methods:

Source code in vllm/platforms/xpu.py
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class XPUPlatform(Platform):
    _enum = PlatformEnum.XPU
    device_name: str = "xpu"
    device_type: str = "xpu"
    dispatch_key: str = "XPU"
    # Intel XPU's device key is "GPU" for Ray.
    # see https://github.com/ray-project/ray/blob/6a5eb5865eeb9ccf058a79b44f107e327e360673/python/ray/_private/accelerators/intel_gpu.py#L20 # noqa: E501
    ray_device_key: str = "GPU"
    dist_backend: str = "xccl"  # xccl only
    device_control_env_var: str = "ZE_AFFINITY_MASK"

    @classmethod
    def import_kernels(cls) -> None:
        # Do not import vllm._C
        with contextlib.suppress(ImportError):
            import vllm._moe_C  # noqa: F401

    @classmethod
    def get_attn_backend_cls(
        cls,
        selected_backend: "AttentionBackendEnum",
        attn_selector_config: "AttentionSelectorConfig",
        num_heads: int | None = None,
    ) -> str:
        from vllm.v1.attention.backends.utils import set_kv_cache_layout

        set_kv_cache_layout("NHD")
        logger.info_once(
            "Setting VLLM_KV_CACHE_LAYOUT to 'NHD' for XPU; "
            "only NHD layout is supported by XPU attention kernels."
        )

        # TurboQuant KV cache: route directly to TQ backend
        kv_cache_dtype = attn_selector_config.kv_cache_dtype
        if kv_cache_dtype is not None and kv_cache_dtype.startswith("turboquant_"):
            logger.info_once("Using TurboQuant attention backend.")
            return AttentionBackendEnum.TURBOQUANT.get_path()

        dtype = attn_selector_config.dtype
        if attn_selector_config.use_sparse:
            logger.info_once("Using XPU MLA Sparse backend.")
            return AttentionBackendEnum.XPU_MLA_SPARSE.get_path()
        if attn_selector_config.use_mla:
            logger.info_once("Using Triton MLA backend on V1 engine.")
            return AttentionBackendEnum.TRITON_MLA.get_path()
        if selected_backend == AttentionBackendEnum.TRITON_ATTN:
            logger.info_once("Using Triton backend.")
            return AttentionBackendEnum.TRITON_ATTN.get_path()
        elif attn_selector_config.use_mm_prefix:
            # Flash Attention on XPU has no FA4 kernel, so it cannot apply the
            # multimodal prefix-LM bidirectional mask. Fall back to Triton
            # Attention, which supports mm_prefix.
            logger.warning_once(
                "Flash Attention on XPU does not support multimodal prefix-LM "
                "attention. Falling back to Triton Attention backend."
            )
            return AttentionBackendEnum.TRITON_ATTN.get_path()
        elif dtype == torch.float32:
            logger.warning_once(
                "Flash Attention on XPU does not support float32 dtype. "
                "Falling back to Triton Attention backend."
            )
            return AttentionBackendEnum.TRITON_ATTN.get_path()
        elif selected_backend == AttentionBackendEnum.FLASH_ATTN:
            logger.info_once("Using Flash Attention backend.")
            return AttentionBackendEnum.FLASH_ATTN.get_path()
        elif selected_backend:
            raise ValueError(
                f"Invalid attention backend for {cls.device_name}, "
                f"with use_mla: {attn_selector_config.use_mla}"
            )

        logger.info_once("Using Flash Attention backend.")
        return AttentionBackendEnum.FLASH_ATTN.get_path()

    @classmethod
    def get_supported_vit_attn_backends(cls) -> list["AttentionBackendEnum"]:
        return [
            AttentionBackendEnum.FLASH_ATTN,
            AttentionBackendEnum.TRITON_ATTN,
            AttentionBackendEnum.TORCH_SDPA,
        ]

    @classmethod
    def get_vit_attn_backend(
        cls,
        head_size: int,
        dtype: torch.dtype,
        backend: "AttentionBackendEnum | None" = None,
    ) -> "AttentionBackendEnum":
        if dtype == torch.float32:
            logger.warning_once(
                "Flash Attention on XPU does not support float32 dtype. "
                "Falling back to Triton Attention backend for vit attention."
            )
            return AttentionBackendEnum.TRITON_ATTN

        if backend is not None:
            assert backend in cls.get_supported_vit_attn_backends(), (
                f"Backend {backend} is not supported for vit attention. "
                f"Supported backends are: "
                f"{cls.get_supported_vit_attn_backends()}."
            )
            logger.info_once(f"Using backend {backend} for vit attention")
            return backend

        logger.info_once(
            f"Using backend {AttentionBackendEnum.FLASH_ATTN} for vit attention"
        )
        return AttentionBackendEnum.FLASH_ATTN

    @classmethod
    def set_device(cls, device: torch.device) -> None:
        """
        Set the device for the current platform.
        """
        torch.xpu.set_device(device)

    @classmethod
    def manual_seed_all(cls, seed: int) -> None:
        torch.xpu.manual_seed_all(seed)

    @classmethod
    def get_device_capability(
        cls,
        device_id: int = 0,
    ) -> DeviceCapability | None:
        # capacity format differs from cuda's and will cause unexpected
        # failure, so use None directly
        return None

    @classmethod
    def get_device_name(cls, device_id: int = 0) -> str:
        return torch.xpu.get_device_name(device_id)

    @classmethod
    def get_punica_wrapper(cls) -> str:
        xpu_use_triton_kernel = os.getenv("XPU_USE_TRITON_KERNEL", "0") == "1"
        if not xpu_use_triton_kernel:
            return "vllm.lora.punica_wrapper.punica_xpu.PunicaWrapperXPU"
        else:
            return "vllm.lora.punica_wrapper.punica_gpu.PunicaWrapperGPU"

    @classmethod
    def get_device_total_memory(cls, device_id: int = 0) -> int:
        device_props = torch.xpu.get_device_properties(device_id)
        return device_props.total_memory

    @classmethod
    def inference_mode(cls):
        return torch.no_grad()

    @classmethod
    def get_static_graph_wrapper_cls(cls) -> str:
        return "vllm.compilation.cuda_graph.CUDAGraphWrapper"

    @classmethod
    def check_and_update_config(cls, vllm_config: VllmConfig) -> None:
        # lazy import to avoid circular import
        from vllm.config import CUDAGraphMode

        compilation_config = vllm_config.compilation_config
        if compilation_config.compile_sizes is None:
            compilation_config.compile_sizes = []

        attention_config = vllm_config.attention_config
        if attention_config.backend is None:
            attention_config.backend = AttentionBackendEnum.FLASH_ATTN

        # lazy import to avoid circular import
        from vllm.utils.torch_utils import supports_xpu_graph

        if not supports_xpu_graph():
            compilation_config.cudagraph_mode = CUDAGraphMode.NONE
            logger.warning_once(
                "XPU Graph is not supported in the current PyTorch version, "
                "disabling cudagraph_mode."
            )
        elif not envs.VLLM_XPU_ENABLE_XPU_GRAPH:
            compilation_config.cudagraph_mode = CUDAGraphMode.NONE
            logger.warning_once(
                "XPU Graph is disabled by environment variable, "
                "please set VLLM_XPU_ENABLE_XPU_GRAPH=1 to enable it."
            )

        # Disable fusion passes not yet supported on XPU.
        from vllm.config.compilation import CompilationMode

        pass_config = compilation_config.pass_config
        fusion_passes_to_disable = {
            "fuse_gemm_comms": "Async TP",
            "fuse_allreduce_rms": "AllReduce + RMSNorm fusion",
            "fuse_attn_quant": "Attention + quant fusion",
            "fuse_act_padding": "Activation + padding fusion",
            "fuse_rope_kvcache": "RoPE + KV cache fusion",
        }
        if compilation_config.mode != CompilationMode.NONE:
            for flag, feature_name in fusion_passes_to_disable.items():
                if getattr(pass_config, flag):
                    logger.warning_once(
                        "Feature %r is not yet supported on XPU and will be disabled.",
                        feature_name,
                    )
                    setattr(pass_config, flag, False)

        # check and update parallel config
        parallel_config = vllm_config.parallel_config
        # Only override worker_cls if it's still the default "auto"
        # This allows custom workers (like vllm-omni workers) to be used on XPU
        if parallel_config.worker_cls == "auto":
            parallel_config.worker_cls = "vllm.v1.worker.xpu_worker.XPUWorker"
        if vllm_config.kv_transfer_config is not None:
            vllm_config.kv_transfer_config.enable_permute_local_kv = True

        # In some cases, the internal memory type cache can misdetect GPU
        # memory as host memory, also leading to invalid memory access.
        # This cache can be disabled by setting UCX_MEMTYPE_CACHE=n.
        # ref. https://openucx.readthedocs.io/en/master/faq.html
        os.environ["UCX_MEMTYPE_CACHE"] = "n"

        # spawn is the only supported multiprocessing method on XPU
        if "VLLM_WORKER_MULTIPROC_METHOD" not in os.environ:
            os.environ["VLLM_WORKER_MULTIPROC_METHOD"] = "spawn"

        # XPU requires graceful shutdown to allow oneCCL/Level Zero resources
        # to be properly released. Without this, subsequent server startups on
        # the same devices may hang during CCL initialization.
        if vllm_config.shutdown_timeout == 0:
            vllm_config.shutdown_timeout = 5
            logger.info(
                "XPU platform: set server shutdown_timeout=%d.",
                vllm_config.shutdown_timeout,
            )

    @classmethod
    def update_block_size_for_backend(cls, vllm_config: "VllmConfig") -> None:
        super().update_block_size_for_backend(vllm_config)
        from vllm.config.vllm import get_layers_from_vllm_config
        from vllm.model_executor.layers.attention_layer_base import (
            AttentionLayerBase,
        )
        from vllm.utils.math_utils import cdiv

        cache_config = vllm_config.cache_config
        # special fix for GDN since kernel only supports block size dividable by 64
        attn_layers = get_layers_from_vllm_config(
            vllm_config,
            AttentionLayerBase,  # type: ignore[type-abstract]
        )

        kernel_block_size = None
        for layer in attn_layers.values():
            b = layer.get_attn_backend()
            if b.get_name() == "GDN_ATTN":
                kernel_block_size = 64
                break

        if kernel_block_size is None:
            return
        new_block_size = (
            cdiv(cache_config.block_size, kernel_block_size) * kernel_block_size
        )
        if new_block_size == cache_config.block_size:
            return

        if cache_config.mamba_cache_mode == "align":
            cache_config.mamba_block_size = new_block_size
        original_mamba_page_size_padded = cache_config.mamba_page_size_padded
        if cache_config.mamba_page_size_padded is not None:
            attn_page_size_1_token = (
                cache_config.mamba_page_size_padded // cache_config.block_size
            )
            cache_config.mamba_page_size_padded = (
                new_block_size * attn_page_size_1_token
            )
        cache_config.block_size = new_block_size
        logger.info(
            "[XPU]Setting attention block size to %d tokens to ensure multiple of %d, "
            "set mamba_page_size_padded to %d bytes accordingly, before was %d bytes.",
            new_block_size,
            kernel_block_size,
            cache_config.mamba_page_size_padded,
            original_mamba_page_size_padded,
        )

    @classmethod
    def support_hybrid_kv_cache(cls) -> bool:
        return True

    @classmethod
    def support_static_graph_mode(cls) -> bool:
        return True

    @classmethod
    def is_pin_memory_available(cls):
        return True

    @classmethod
    def get_current_memory_usage(
        cls, device: torch.types.Device | None = None
    ) -> float:
        torch.xpu.empty_cache()
        torch.xpu.reset_peak_memory_stats(device)
        return torch.xpu.max_memory_allocated(device)

    @classmethod
    def fp8_dtype(cls) -> torch.dtype:
        return torch.float8_e4m3fn

    @classmethod
    def is_data_center_gpu(cls) -> bool:
        device_name = cls.get_device_name().lower()
        return device_name.count("data center gpu") > 0

    @classmethod
    def get_device_communicator_cls(cls) -> str:
        if not torch.distributed.is_xccl_available():
            # Supports xccl with PyTorch versions >= 2.8.0.dev for XPU platform
            logger.warning(
                "xccl is not enabled in this torch build, communication"
                " is not available."
            )
        return "vllm.distributed.device_communicators.xpu_communicator.XpuCommunicator"  # noqa

    @classmethod
    def supports_fp8(cls) -> bool:
        return True

    @classmethod
    def get_default_ir_op_priority(
        cls, vllm_config: "VllmConfig"
    ) -> "IrOpPriorityConfig":
        from vllm.config.compilation import CompilationMode
        from vllm.config.kernel import IrOpPriorityConfig

        # Native used by default when compiling,
        # use fused kernels where available when no codegen
        cc = vllm_config.compilation_config
        using_inductor = cc.backend == "inductor" and cc.mode != CompilationMode.NONE
        default = ["native"] if using_inductor else ["xpu_kernels", "native"]

        return IrOpPriorityConfig.with_default(default)

    @classmethod
    def device_count(cls) -> int:
        return torch.xpu.device_count()

    @classmethod
    def check_if_supports_dtype(cls, dtype: torch.dtype):
        if dtype == torch.bfloat16:  # noqa: SIM102
            device_name = cls.get_device_name().lower()
            # client gpu a770
            if device_name.count("a770") > 0:
                raise ValueError(
                    "Intel Arc A770 have bfloat16 accuracy known issue. "
                    "You can use float16 instead by explicitly setting the "
                    "`dtype` flag in CLI, for example: --dtype=half."
                )

    @classmethod
    def opaque_attention_op(cls) -> bool:
        return True

    @classmethod
    def insert_blocks_to_device(
        cls,
        src_cache: torch.Tensor,
        dst_cache: torch.Tensor,
        src_block_indices: torch.Tensor,
        dst_block_indices: torch.Tensor,
    ) -> None:
        """Copy blocks from src_cache to dst_cache on XPU."""
        _src_cache = src_cache[src_block_indices]
        dst_cache[dst_block_indices] = _src_cache.to(dst_cache.device)

    @classmethod
    def swap_out_blocks_to_host(
        cls,
        src_cache: torch.Tensor,
        dst_cache: torch.Tensor,
        src_block_indices: torch.Tensor,
        dst_block_indices: torch.Tensor,
    ) -> None:
        """Copy blocks from XPU to host (CPU)."""
        _src_cache = src_cache[src_block_indices]
        dst_cache[dst_block_indices] = _src_cache.cpu()

    @classmethod
    def num_compute_units(cls, device_id: int = 0) -> int:
        return torch.xpu.get_device_properties(device_id).max_compute_units

    @classmethod
    def use_custom_op_collectives(cls) -> bool:
        return True

insert_blocks_to_device(src_cache, dst_cache, src_block_indices, dst_block_indices) classmethod

Copy blocks from src_cache to dst_cache on XPU.

Source code in vllm/platforms/xpu.py
@classmethod
def insert_blocks_to_device(
    cls,
    src_cache: torch.Tensor,
    dst_cache: torch.Tensor,
    src_block_indices: torch.Tensor,
    dst_block_indices: torch.Tensor,
) -> None:
    """Copy blocks from src_cache to dst_cache on XPU."""
    _src_cache = src_cache[src_block_indices]
    dst_cache[dst_block_indices] = _src_cache.to(dst_cache.device)

set_device(device) classmethod

Set the device for the current platform.

Source code in vllm/platforms/xpu.py
@classmethod
def set_device(cls, device: torch.device) -> None:
    """
    Set the device for the current platform.
    """
    torch.xpu.set_device(device)

swap_out_blocks_to_host(src_cache, dst_cache, src_block_indices, dst_block_indices) classmethod

Copy blocks from XPU to host (CPU).

Source code in vllm/platforms/xpu.py
@classmethod
def swap_out_blocks_to_host(
    cls,
    src_cache: torch.Tensor,
    dst_cache: torch.Tensor,
    src_block_indices: torch.Tensor,
    dst_block_indices: torch.Tensor,
) -> None:
    """Copy blocks from XPU to host (CPU)."""
    _src_cache = src_cache[src_block_indices]
    dst_cache[dst_block_indices] = _src_cache.cpu()

get_mem_info_wrapper(device=None)

Get memory info for a device, compatible with torch.accelerator.get_memory_info API.

Parameters:

  • device

    (int | str | device | None, default: None ) –

    Device specification. Can be: - None: Use current XPU device - int: Device index - str: Device string (e.g., "xpu:0", "xpu") - torch.device: Device object

Returns:

  • tuple[int, int]

    Tuple[int, int]: (free_memory, total_memory) in bytes

Source code in vllm/platforms/xpu.py
def get_mem_info_wrapper(
    device: int | str | torch.device | None = None,
) -> tuple[int, int]:
    """
    Get memory info for a device, compatible with torch.accelerator.get_memory_info API.

    Args:
        device: Device specification. Can be:
            - None: Use current XPU device
            - int: Device index
            - str: Device string (e.g., "xpu:0", "xpu")
            - torch.device: Device object

    Returns:
        Tuple[int, int]: (free_memory, total_memory) in bytes
    """
    # Handle None - use current device
    if device is None:
        device = torch.xpu.current_device()

    # Handle torch.device objects
    elif isinstance(device, torch.device):
        if device.type != "xpu":
            raise RuntimeError(f"Expected 'xpu' device, got '{device.type}'")
        # If device index is not specified, use current device
        device = (
            device.index if device.index is not None else torch.xpu.current_device()
        )

    # Handle string device specifications (e.g., "xpu:0", "xpu")
    elif isinstance(device, str):
        if not device.startswith("xpu"):
            raise RuntimeError(f"Expected 'xpu' device string, got '{device}'")
        # Parse device string
        parts = device.split(":")
        if len(parts) == 1:
            # "xpu" -> use current device
            device = torch.xpu.current_device()
        elif len(parts) == 2:
            # "xpu:0" -> use index 0
            try:
                device = int(parts[1])
            except ValueError as err:
                raise RuntimeError(
                    f"Invalid device index: '{device}', expected integer after ':'"
                ) from err
        else:
            raise RuntimeError(f"Invalid device string format: '{device}'")

    # At this point, device should be an int
    if isinstance(device, int):
        # bounds check
        device_count = torch.xpu.device_count()
        if not (0 <= device < device_count):
            raise ValueError(
                f"Invalid device index {device}, must be in range [0, {device_count})"
            )

    elif not isinstance(device, int):
        raise TypeError(
            f"device must be int, str, torch.device, or None, got {type(device)}"
        )

    # Call the underlying C++ implementation
    free, total = torch.ops._C_cache_ops.getMemoryInfo(device)

    return free, total