vllm.model_executor.layers.fused_moe.oracle.base ¶

class MoEKernelOracle(ABC, Generic[BackendT]):
    """Abstract base for MoE kernel-selection oracles.

    Concrete oracles MUST implement: `backend_enum_cls`,
    `get_priority_backends`, `backend_to_kernel_cls`, `map_backend`,
    `select_backend`, `make_kernel`.

    Concrete oracles MAY override: `convert_to_kernel_format`,
    `make_quant_config`. The base class provides default implementations
    that are appropriate for oracles which do not need them
    (e.g. `make_quant_config` raises on the unquantized oracle).
    """

    @abstractmethod
    def backend_enum_cls(self) -> type[BackendT]:
        """Return the concrete `Enum` class enumerating this oracle's
        backends (e.g. `UnquantizedMoeBackend`, `Fp8MoeBackend`)."""

    @abstractmethod
    def get_priority_backends(self, moe_config: FusedMoEConfig) -> list[BackendT]:
        """Return platform-appropriate backends in priority order for
        this `moe_config`."""

    @abstractmethod
    def backend_to_kernel_cls(self, backend: BackendT) -> type[mk.FusedMoEExperts]:
        """Map a backend enum value to its concrete `FusedMoEExperts`
        subclass."""

    @abstractmethod
    def map_backend(self, runner_backend: MoEBackend) -> BackendT:
        """Map a user-facing `MoEBackend` (from the runner config) to
        this oracle's enum."""

    @abstractmethod
    def select_backend(
        self,
        moe_config: FusedMoEConfig,
        weight_key: "QuantKey | None" = None,
        activation_key: "QuantKey | None" = None,
    ) -> tuple[BackendT, type[mk.FusedMoEExperts] | None]:
        """Primary entry point: choose the best supported backend for
        the given `moe_config`.

        `weight_key` / `activation_key` carry the quantization scheme of
        the weights and activations and are consumed by quantized oracles
        (fp8, nvfp4, int8, ...) to disambiguate backends. The unquantized
        oracle ignores them. Subclasses with additional selection inputs
        (e.g. int_wna16 needs `weight_bits`, fp8 needs
        `allow_vllm_cutlass`) widen the signature in their override; a
        per-oracle config object is the longer-term target tracked in
        the #37753 follow-up PRs.
        """

    @abstractmethod
    def make_kernel(
        self,
        quant_config: FusedMoEQuantConfig,
        moe_config: FusedMoEConfig,
        backend: BackendT,
        experts_cls: type[mk.FusedMoEExperts],
        routing_tables: tuple[torch.Tensor, torch.Tensor, torch.Tensor] | None = None,
    ) -> mk.FusedMoEKernel:
        """Construct the `FusedMoEKernel` (Prepare/Finalize + Experts
        combinator) for the chosen backend."""

    def convert_to_kernel_format(
        self,
        backend: BackendT,
        moe_config: FusedMoEConfig,
        w13_weight: torch.Tensor,
        w2_weight: torch.Tensor,
    ) -> tuple[torch.Tensor, torch.Tensor]:
        """Shuffle weights into the layout expected by `backend`.

        Default implementation returns the inputs unchanged. Oracles
        whose backends need weight permutation should override this
        (e.g. `UnquantizedMoEKernelOracle` handles AITER and FlashInfer
        layouts).

        `moe_config` carries MoE-layer state (e.g. `is_act_and_mul`)
        that the conversion needs without coupling the oracle to a
        `Module` reference. Quantized oracles whose conversion
        additionally needs scales / zero-points / block shapes will
        override with a wider signature (and ultimately a per-oracle
        config object — tracked in the #37753 follow-up PRs).
        """
        return w13_weight, w2_weight

    def make_quant_config(self, *args, **kwargs) -> FusedMoEQuantConfig:
        """Build a `FusedMoEQuantConfig` for this oracle.

        Quantized oracles (fp8, nvfp4, mxfp4, ...) override this with
        the appropriate signature for their quantization scheme.
        Unquantized oracles inherit the default, which raises because
        there is no quantization-specific config to build.
        """
        raise NotImplementedError(
            f"{type(self).__name__} does not implement make_quant_config; "
            "this oracle has no quantization-specific config to build."
        )