# Adapted from https://github.com/vllm-project/vllm/blob/v0.6.4.post1/vllm/model_executor/layers/quantization/fp8.py

from __future__ import annotations

import logging
from typing import TYPE_CHECKING, Any, Dict, List, Optional, Union

import torch
import torch.nn.functional as F
from torch.nn import Module
from torch.nn.parameter import Parameter

try:
    from vllm.model_executor.layers.quantization.utils.marlin_utils_fp8 import (
        apply_fp8_marlin_linear,
        prepare_fp8_layer_for_marlin,
    )

    MARLIN_FP8_AVAILABLE = True
except ImportError:
    MARLIN_FP8_AVAILABLE = False

    def dummy_func(*args, **kwargs):
        raise ImportError(
            "marlin FP8 requires some operators from vllm. Please install vllm."
        )

    apply_fp8_marlin_linear = prepare_fp8_layer_for_marlin = dummy_func


from sglang.srt.distributed import get_tensor_model_parallel_world_size
from sglang.srt.layers.amx_utils import _amx_process_weight_after_loading
from sglang.srt.layers.moe import MoeRunner, MoeRunnerBackend, MoeRunnerConfig
from sglang.srt.layers.moe.moe_runner.triton import TritonMoeQuantInfo
from sglang.srt.layers.moe.token_dispatcher.base import DispatchOutputChecker
from sglang.srt.layers.parameter import (
    BlockQuantScaleParameter,
    ModelWeightParameter,
    PerTensorScaleParameter,
)
from sglang.srt.layers.quantization.base_config import (
    FusedMoEMethodBase,
    LinearMethodBase,
    QuantizationConfig,
    QuantizeMethodBase,
)
from sglang.srt.layers.quantization.fp8_kernel import (
    fp8_dtype,
    is_fp8_fnuz,
    per_token_group_quant_fp8,
    scaled_fp8_quant,
)
from sglang.srt.layers.quantization.fp8_utils import (
    apply_fp8_linear,
    can_auto_enable_marlin_fp8,
    cutlass_fp8_supported,
    dispatch_w8a8_block_fp8_linear,
    input_to_float8,
    normalize_e4m3fn_to_e4m3fnuz,
)
from sglang.srt.layers.quantization.kv_cache import BaseKVCacheMethod
from sglang.srt.layers.quantization.unquant import UnquantizedLinearMethod
from sglang.srt.layers.quantization.utils import (
    all_close_1d,
    convert_to_channelwise,
    is_layer_skipped,
    per_tensor_dequantize,
    requantize_with_max_scale,
)
from sglang.srt.utils import (
    cpu_has_amx_support,
    get_bool_env_var,
    is_cpu,
    is_cuda,
    is_hip,
    is_npu,
    is_sm90_supported,
    is_sm100_supported,
    log_info_on_rank0,
    next_power_of_2,
    print_warning_once,
    set_weight_attrs,
    use_intel_amx_backend,
)

if TYPE_CHECKING:
    from sglang.srt.layers.moe.token_dispatcher import (
        CombineInput,
        DispatchOutput,
        StandardDispatchOutput,
    )
    from sglang.srt.layers.moe.topk import TopKOutput
    from sglang.srt.layers.quantization.w4afp8 import W4AFp8Config

_is_hip = is_hip()
_is_cuda = is_cuda()
_is_npu = is_npu()
_is_cpu_amx_available = cpu_has_amx_support()
_is_cpu = is_cpu()

_is_fp8_fnuz = is_fp8_fnuz()

_use_hip_int4 = get_bool_env_var("SGLANG_INT4_WEIGHT")
_use_aiter = get_bool_env_var("SGLANG_USE_AITER") and _is_hip

if _is_hip and (_use_aiter or _use_hip_int4):
    from aiter import ActivationType, QuantType
    from aiter.fused_moe import fused_moe
    from aiter.ops.shuffle import shuffle_weight


ACTIVATION_SCHEMES = ["static", "dynamic"]

logger = logging.getLogger(__name__)


class Fp8Config(QuantizationConfig):
    """Config class for FP8."""

    def __init__(
        self,
        is_checkpoint_fp8_serialized: bool = False,
        activation_scheme: str = "dynamic",
        ignored_layers: Optional[List[str]] = None,
        weight_block_size: List[int] = None,
    ) -> None:
        self.is_checkpoint_fp8_serialized = is_checkpoint_fp8_serialized
        if is_checkpoint_fp8_serialized:
            log_info_on_rank0(logger, "Detected fp8 checkpoint.")
        if activation_scheme not in ACTIVATION_SCHEMES:
            raise ValueError(f"Unsupported activation scheme {activation_scheme}")
        self.activation_scheme = activation_scheme
        self.ignored_layers = ignored_layers or []
        if weight_block_size is not None:
            if not is_checkpoint_fp8_serialized:
                raise ValueError(
                    f"The block-wise quantization only supports fp8-serialized checkpoint for now."
                )
            if len(weight_block_size) != 2:
                raise ValueError(
                    f"The quantization block size of weight must have 2 dimensions, but got {len(weight_block_size)} dimensions."
                )
            if activation_scheme != "dynamic":
                raise ValueError(
                    f"The block-wise quantization only supports dynamic activation scheme for now, but got {activation_scheme} activation scheme."
                )
        self.weight_block_size = weight_block_size

    @classmethod
    def get_name(cls) -> str:
        return "fp8"

    @classmethod
    def get_supported_act_dtypes(cls) -> List[torch.dtype]:
        return [torch.bfloat16, torch.half]

    @classmethod
    def get_min_capability(cls) -> int:
        return 80

    @classmethod
    def get_config_filenames(cls) -> List[str]:
        return []

    @classmethod
    def from_config(cls, config: Dict[str, Any]) -> Fp8Config:
        quant_method = cls.get_from_keys(config, ["quant_method"])
        is_checkpoint_fp8_serialized = "fp8" in quant_method
        activation_scheme = cls.get_from_keys(config, ["activation_scheme"])
        ignored_layers = cls.get_from_keys_or(config, ["ignored_layers"], None)
        weight_block_size = cls.get_from_keys_or(config, ["weight_block_size"], None)
        return cls(
            is_checkpoint_fp8_serialized=is_checkpoint_fp8_serialized,
            activation_scheme=activation_scheme,
            ignored_layers=ignored_layers,
            weight_block_size=weight_block_size,
        )

    def get_quant_method(
        self, layer: torch.nn.Module, prefix: str
    ) -> Optional[QuantizeMethodBase]:
        from sglang.srt.layers.linear import LinearBase
        from sglang.srt.layers.moe.fused_moe_triton import FusedMoE

        if isinstance(layer, LinearBase):
            if is_layer_skipped(prefix, self.ignored_layers):
                return UnquantizedLinearMethod()
            return Fp8LinearMethod(self)
        elif isinstance(layer, FusedMoE):
            return Fp8MoEMethod(self)
        return None

    def get_scaled_act_names(self) -> List[str]:
        return []


class Fp8LinearMethod(LinearMethodBase):
    """Linear method for FP8.
    Supports loading FP8 checkpoints with static weight scale and
    dynamic/static activation scale.

    Also supports loading quantized FP16/BF16 model checkpoints with dynamic
    activation scaling. The weight scaling factor will be initialized after
    the model weights are loaded.

    Limitations:
    1. Only support per-tensor quantization due to torch._scaled_mm support.
    2. Only support float8_e4m3fn data type due to the limitation of
       torch._scaled_mm (https://github.com/pytorch/pytorch/blob/2e48b39603411a41c5025efbe52f89560b827825/aten/src/ATen/native/cuda/Blas.cpp#L854-L856)

    Args:
        quant_config: The quantization config.
    """

    def __init__(self, quant_config: Union[Fp8Config, W4AFp8Config]):
        self.quant_config = quant_config
        self.cutlass_fp8_supported = cutlass_fp8_supported()

        # For GPUs that lack FP8 hardware support, we can leverage the Marlin
        # kernel for fast weight-only FP8 quantization
        self.use_marlin = False
        if _is_cuda and MARLIN_FP8_AVAILABLE:
            force_marlin = get_bool_env_var("SGLANG_FORCE_FP8_MARLIN")
            auto_enable = can_auto_enable_marlin_fp8()
            self.use_marlin = force_marlin or auto_enable

        self.block_quant = self.quant_config.weight_block_size is not None

        self.w8a8_block_fp8_linear = dispatch_w8a8_block_fp8_linear()

    def create_weights(
        self,
        layer: torch.nn.Module,
        input_size_per_partition: int,
        output_partition_sizes: List[int],
        input_size: int,
        output_size: int,
        params_dtype: torch.dtype,
        **extra_weight_attrs,
    ):
        output_size_per_partition = sum(output_partition_sizes)
        weight_loader = extra_weight_attrs.get("weight_loader")

        tp_size = get_tensor_model_parallel_world_size()
        if self.block_quant:
            block_n, block_k = (
                self.quant_config.weight_block_size[0],
                self.quant_config.weight_block_size[1],
            )
            # Required by row parallel
            if tp_size > 1 and input_size // input_size_per_partition == tp_size:
                if input_size_per_partition % block_k != 0:
                    raise ValueError(
                        f"Weight input_size_per_partition = "
                        f"{input_size_per_partition} is not divisible by "
                        f"weight quantization block_k = {block_k}."
                    )
            # Required by column parallel or enabling merged weights
            if (
                tp_size > 1 and output_size // output_size_per_partition == tp_size
            ) or len(output_partition_sizes) > 1:
                for output_partition_size in output_partition_sizes:
                    if output_partition_size % block_n != 0:
                        raise ValueError(
                            f"Weight output_partition_size = "
                            f"{output_partition_size} is not divisible by "
                            f"weight quantization block_n = {block_n}."
                        )

        layer.logical_widths = output_partition_sizes
        layer.input_size_per_partition = input_size_per_partition
        layer.output_size_per_partition = output_size_per_partition
        layer.orig_dtype = params_dtype

        # WEIGHT
        weight_dtype = (
            torch.float8_e4m3fn
            if self.quant_config.is_checkpoint_fp8_serialized
            else params_dtype
        )

        weight = ModelWeightParameter(
            data=torch.empty(
                output_size_per_partition, input_size_per_partition, dtype=weight_dtype
            ),
            input_dim=1,
            output_dim=0,
            weight_loader=weight_loader,
        )
        layer.register_parameter("weight", weight)

        # If checkpoint is serialized fp8, load them.
        # Otherwise, wait until process_weights_after_loading.
        if self.quant_config.is_checkpoint_fp8_serialized:
            # WEIGHT SCALE
            if self.block_quant:
                if hasattr(self.quant_config, "activation_scheme"):
                    assert self.quant_config.activation_scheme == "dynamic"
                elif hasattr(self.quant_config, "linear_activation_scheme"):
                    assert self.quant_config.linear_activation_scheme == "dynamic"
                scale = BlockQuantScaleParameter(
                    data=torch.empty(
                        (output_size_per_partition + block_n - 1) // block_n,
                        (input_size_per_partition + block_k - 1) // block_k,
                        dtype=torch.float32,
                    ),
                    input_dim=1,
                    output_dim=0,
                    weight_loader=weight_loader,
                )
                scale[:] = torch.finfo(torch.float32).min
                layer.register_parameter("weight_scale_inv", scale)
            else:
                scale = PerTensorScaleParameter(
                    data=torch.empty(len(output_partition_sizes), dtype=torch.float32),
                    weight_loader=weight_loader,
                )
                scale[:] = torch.finfo(torch.float32).min
                layer.register_parameter("weight_scale", scale)

            # INPUT ACTIVATION SCALE
            if (
                hasattr(self.quant_config, "activation_scheme")
                and self.quant_config.activation_scheme == "static"
            ) or (
                hasattr(self.quant_config, "linear_activation_scheme")
                and self.quant_config.linear_activation_scheme == "static"
            ):
                scale = PerTensorScaleParameter(
                    data=torch.empty(len(output_partition_sizes), dtype=torch.float32),
                    weight_loader=weight_loader,
                )

                scale[:] = torch.finfo(torch.float32).min
                layer.register_parameter("input_scale", scale)
            else:
                layer.register_parameter("input_scale", None)

    def process_weights_after_loading(self, layer: Module) -> None:
        if self.block_quant:
            # If ROCm, normalize the weights and scales to e4m3fnuz
            if _is_fp8_fnuz:
                # activation_scheme: dynamic
                weight, weight_scale, _ = normalize_e4m3fn_to_e4m3fnuz(
                    weight=layer.weight,
                    weight_scale=layer.weight_scale_inv,
                    input_scale=None,
                )
                layer.input_scale = None
            elif _is_cpu:
                assert (
                    _is_cpu_amx_available
                ), "Fp8LinearMethod on CPU requires that CPU has AMX support"
                _amx_process_weight_after_loading(layer, ["weight"])
                layer.weight_scale_inv = torch.nn.Parameter(
                    layer.weight_scale_inv.data, requires_grad=False
                )
                return
            else:
                weight, weight_scale = layer.weight.data, layer.weight_scale_inv.data
            layer.weight = Parameter(weight, requires_grad=False)
            layer.weight_scale_inv = Parameter(weight_scale, requires_grad=False)
        else:
            layer.weight = Parameter(layer.weight.data, requires_grad=False)

            # If checkpoint not serialized fp8, quantize the weights.
            if not self.quant_config.is_checkpoint_fp8_serialized:
                if self.cutlass_fp8_supported or self.use_marlin:
                    # apply per-channel quantization default as
                    # cutlass sgl-kernel and marlin only support per-channel scale
                    qweight, weight_scale = per_token_group_quant_fp8(
                        layer.weight, layer.weight.shape[-1]
                    )
                    weight_scale = weight_scale.t().contiguous()
                else:
                    # per-tensor quantization
                    qweight, weight_scale = input_to_float8(layer.weight)

                # Update the layer with the new values.
                layer.weight = Parameter(qweight.t(), requires_grad=False)
                layer.weight_scale = Parameter(weight_scale, requires_grad=False)
                layer.input_scale = None

            # If checkpoint is fp8, handle that there are N scales for N
            # shards in a fused module
            else:
                layer.weight_scale = Parameter(
                    layer.weight_scale.data, requires_grad=False
                )
                if (
                    hasattr(self.quant_config, "activation_scheme")
                    and self.quant_config.activation_scheme == "static"
                ) or (
                    hasattr(self.quant_config, "linear_activation_scheme")
                    and self.quant_config.linear_activation_scheme == "static"
                ):
                    layer.input_scale = Parameter(
                        layer.input_scale.data, requires_grad=False
                    )

                # cutlass sgl-kernel and marlin only support per-channel scale
                if self.cutlass_fp8_supported or self.use_marlin:
                    weight = layer.weight
                    weight_scale = convert_to_channelwise(
                        layer.weight_scale, layer.logical_widths
                    )
                else:
                    # Dequant -> Quant with max scale so we can run per tensor.
                    weight = layer.weight
                    weight_scale = layer.weight_scale
                    # If ROCm, normalize the weights and scales to e4m3fnuz
                    if _is_fp8_fnuz:
                        weight, weight_scale, input_scale = (
                            normalize_e4m3fn_to_e4m3fnuz(
                                weight=weight,
                                weight_scale=weight_scale,
                                input_scale=layer.input_scale,
                            )
                        )
                        if input_scale is not None:
                            layer.input_scale = Parameter(
                                input_scale, requires_grad=False
                            )

                    weight_scale, weight = requantize_with_max_scale(
                        weight=weight,
                        weight_scale=weight_scale,
                        logical_widths=layer.logical_widths,
                    )

                # Update layer with new values.
                layer.weight = Parameter(weight.t(), requires_grad=False)
                layer.weight_scale = Parameter(weight_scale, requires_grad=False)
                if (
                    hasattr(self.quant_config, "activation_scheme")
                    and self.quant_config.activation_scheme == "static"
                ) or (
                    hasattr(self.quant_config, "linear_activation_scheme")
                    and self.quant_config.linear_activation_scheme == "static"
                ):
                    layer.input_scale = Parameter(
                        layer.input_scale.max(), requires_grad=False
                    )

        if self.use_marlin:
            if self.block_quant:
                layer.weight_block_size = self.quant_config.weight_block_size
            prepare_fp8_layer_for_marlin(layer, not self.block_quant)
            # Activations not quantized for marlin.
            del layer.input_scale

    def apply(
        self,
        layer: torch.nn.Module,
        x: torch.Tensor,
        bias: Optional[torch.Tensor] = None,
    ) -> torch.Tensor:
        if self.use_marlin:
            return apply_fp8_marlin_linear(
                input=x,
                weight=layer.weight,
                weight_scale=layer.weight_scale,
                workspace=layer.workspace,
                size_n=layer.output_size_per_partition,
                size_k=layer.input_size_per_partition,
                bias=bias,
            )

        if self.block_quant:
            if use_intel_amx_backend(layer):
                return torch.ops.sgl_kernel.fp8_scaled_mm_cpu(
                    x,
                    layer.weight,
                    layer.weight_scale_inv,
                    self.quant_config.weight_block_size,
                    bias,
                    x.dtype,
                    True,  # is_vnni
                )

            return self.w8a8_block_fp8_linear(
                input=x,
                weight=layer.weight,
                block_size=self.quant_config.weight_block_size,
                weight_scale=layer.weight_scale_inv,
                input_scale=None,
                bias=bias,
            )

        return apply_fp8_linear(
            input=x,
            weight=layer.weight,
            weight_scale=layer.weight_scale,
            input_scale=layer.input_scale,
            bias=bias,
            cutlass_fp8_supported=self.cutlass_fp8_supported,
            use_per_token_if_dynamic=False,
        )


def get_tile_tokens_dim(num_tokens, top_k, num_experts):
    # Guess tokens per expert assuming perfect expert distribution first.
    num_tokens_per_expert = (num_tokens * top_k) // num_experts
    # And pad the number to the next power of 2.
    tile_tokens_dim = next_power_of_2(num_tokens_per_expert)
    # Cap to 8-64 tokens per CTA tile as it's the range supported by the kernel.
    tile_tokens_dim = min(max(tile_tokens_dim, 8), 64)
    return tile_tokens_dim


class Fp8MoEMethod(FusedMoEMethodBase):
    """MoE method for FP8.
    Supports loading FP8 checkpoints with static weight scale and
    dynamic/static activation scale.

    Also supports loading quantized FP16/BF16 model checkpoints with dynamic
    activation scaling. The weight scaling factor will be initialized after
    the model weights are loaded.

    Args:
        quant_config: The quantization config.
    """

    def __init__(self, quant_config: Fp8Config):
        self.quant_config = quant_config
        self.block_quant = self.quant_config.weight_block_size is not None
        self.cutlass_fp8_supported = cutlass_fp8_supported()
        self.use_cutlass_fused_experts_fp8 = (
            get_bool_env_var("SGLANG_CUTLASS_MOE")
            and self.cutlass_fp8_supported
            and self.block_quant
            and (is_sm100_supported() or is_sm90_supported())
        )

    def create_weights(
        self,
        layer: Module,
        num_experts: int,
        hidden_size: int,
        intermediate_size_per_partition: int,
        params_dtype: torch.dtype,
        **extra_weight_attrs,
    ):
        from sglang.srt.layers.moe.fused_moe_triton import FusedMoeWeightScaleSupported

        if self.quant_config.is_checkpoint_fp8_serialized:
            params_dtype = torch.uint32 if _use_hip_int4 else torch.float8_e4m3fn
        tp_size = get_tensor_model_parallel_world_size()
        if self.block_quant:
            block_n, block_k = (
                self.quant_config.weight_block_size[0],
                self.quant_config.weight_block_size[1],
            )
            # NOTE(HandH1998): To ensure proper alignment of the block-wise quantization scales, the output_size of the weights for both the gate and up layers must be divisible by block_n.
            # Required by column parallel or enabling merged weights
            if intermediate_size_per_partition % block_n != 0:
                raise ValueError(
                    f"The output_size of gate's and up's weight = "
                    f"{intermediate_size_per_partition} is not divisible by "
                    f"weight quantization block_n = {block_n}."
                )
            if tp_size > 1:
                # Required by row parallel
                if intermediate_size_per_partition % block_k != 0:
                    raise ValueError(
                        f"The input_size of down's weight = "
                        f"{intermediate_size_per_partition} is not divisible by "
                        f"weight quantization block_k = {block_k}."
                    )

        # WEIGHTS
        if _is_hip and _use_hip_int4:
            # INT4 MoE weight - INT32 packed
            w13_weight = torch.nn.Parameter(
                torch.empty(
                    num_experts,
                    2 * intermediate_size_per_partition,
                    hidden_size // 8,
                    dtype=params_dtype,
                ),
                requires_grad=False,
            )
            w2_weight = torch.nn.Parameter(
                torch.empty(
                    num_experts,
                    hidden_size,
                    intermediate_size_per_partition // 8,
                    dtype=params_dtype,
                ),
                requires_grad=False,
            )
        else:
            w13_weight = torch.nn.Parameter(
                torch.empty(
                    num_experts,
                    2 * intermediate_size_per_partition,
                    hidden_size,
                    dtype=params_dtype,
                ),
                requires_grad=False,
            )
            w2_weight = torch.nn.Parameter(
                torch.empty(
                    num_experts,
                    hidden_size,
                    intermediate_size_per_partition,
                    dtype=params_dtype,
                ),
                requires_grad=False,
            )

        layer.register_parameter("w13_weight", w13_weight)
        set_weight_attrs(w13_weight, extra_weight_attrs)

        layer.register_parameter("w2_weight", w2_weight)
        set_weight_attrs(w2_weight, extra_weight_attrs)

        # WEIGHT_SCALES
        if self.block_quant:
            w13_weight_scale = torch.nn.Parameter(
                torch.ones(
                    num_experts,
                    2 * ((intermediate_size_per_partition + block_n - 1) // block_n),
                    (hidden_size + block_k - 1) // block_k,
                    dtype=torch.float32,
                ),
                requires_grad=False,
            )
            w2_weight_scale = torch.nn.Parameter(
                torch.ones(
                    num_experts,
                    (hidden_size + block_n - 1) // block_n,
                    (intermediate_size_per_partition + block_k - 1) // block_k,
                    dtype=torch.float32,
                ),
                requires_grad=False,
            )
            layer.register_parameter("w13_weight_scale_inv", w13_weight_scale)
            layer.register_parameter("w2_weight_scale_inv", w2_weight_scale)
            assert self.quant_config.activation_scheme == "dynamic"
            if self.use_cutlass_fused_experts_fp8:
                self.ab_strides1 = torch.full(
                    (num_experts,),
                    hidden_size,
                    device=w13_weight.device,
                    dtype=torch.int64,
                )
                self.c_strides1 = torch.full(
                    (num_experts,),
                    2 * intermediate_size_per_partition,
                    device=w13_weight.device,
                    dtype=torch.int64,
                )
                self.ab_strides2 = torch.full(
                    (num_experts,),
                    intermediate_size_per_partition,
                    device=w2_weight.device,
                    dtype=torch.int64,
                )
                self.c_strides2 = torch.full(
                    (num_experts,),
                    hidden_size,
                    device=w2_weight.device,
                    dtype=torch.int64,
                )
                self.workspace = torch.empty(
                    90000, device=w13_weight.device, dtype=torch.uint8
                )
                self.a_ptr = torch.empty(
                    num_experts, device=w13_weight.device, dtype=torch.int64
                )
                self.b_ptr = torch.empty(
                    num_experts, device=w13_weight.device, dtype=torch.int64
                )
                self.out_ptr = torch.empty(
                    num_experts, device=w13_weight.device, dtype=torch.int64
                )
                self.a_scales_ptr = torch.empty(
                    num_experts, device=w13_weight.device, dtype=torch.int64
                )
                self.b_scales_ptr = torch.empty(
                    num_experts, device=w13_weight.device, dtype=torch.int64
                )
                self.expert_offsets = torch.empty(
                    num_experts + 1, device=w13_weight.device, dtype=torch.int32
                )
                self.problem_sizes1 = torch.empty(
                    num_experts, 3, device=w13_weight.device, dtype=torch.int32
                )
                self.problem_sizes2 = torch.empty(
                    num_experts, 3, device=w13_weight.device, dtype=torch.int32
                )

        else:
            # Allocate 2 scales for w1 and w3 respectively.
            # They will be combined to a single scale after weight loading.
            w13_weight_scale = torch.nn.Parameter(
                torch.ones(num_experts, 2, dtype=torch.float32), requires_grad=False
            )
            w2_weight_scale = torch.nn.Parameter(
                torch.ones(num_experts, dtype=torch.float32), requires_grad=False
            )
            layer.register_parameter("w13_weight_scale", w13_weight_scale)
            layer.register_parameter("w2_weight_scale", w2_weight_scale)

            if _is_hip:  # _use_aiter: TODO: add check back after triton kernel
                # ROCm - using column scaling, duplicate scaling numbers in case per tensor scaling
                w13_weight_scale1 = torch.nn.Parameter(
                    torch.ones(
                        num_experts,
                        2 * intermediate_size_per_partition,
                        dtype=torch.float32,
                    ),
                    requires_grad=False,
                )
                w2_weight_scale1 = torch.nn.Parameter(
                    torch.ones(num_experts, hidden_size, dtype=torch.float32),
                    requires_grad=False,
                )
                layer.register_parameter("w13_weight_scale1", w13_weight_scale1)
                layer.register_parameter("w2_weight_scale1", w2_weight_scale1)

        # Add the quantization method used (per tensor/grouped/channel)
        # to ensure the weight scales are loaded in properly
        extra_weight_attrs.update(
            {"quant_method": FusedMoeWeightScaleSupported.BLOCK.value}
            if self.block_quant
            else {"quant_method": FusedMoeWeightScaleSupported.TENSOR.value}
        )
        # If loading fp8 checkpoint, pass the weight loaders.
        # If loading an fp16 checkpoint, do not (we will quantize in
        #   process_weights_after_loading()
        if self.quant_config.is_checkpoint_fp8_serialized:
            set_weight_attrs(w13_weight_scale, extra_weight_attrs)
            set_weight_attrs(w2_weight_scale, extra_weight_attrs)

            if _is_hip and _use_hip_int4:
                extra_weight_attrs.update(
                    {"quant_method": FusedMoeWeightScaleSupported.CHANNEL.value}
                )
                set_weight_attrs(w13_weight_scale1, extra_weight_attrs)
                set_weight_attrs(w2_weight_scale1, extra_weight_attrs)

        # INPUT_SCALES
        if self.quant_config.activation_scheme == "static":
            if not self.quant_config.is_checkpoint_fp8_serialized:
                raise ValueError(
                    "Found static activation scheme for checkpoint that "
                    "was not serialized fp8."
                )

            w13_input_scale = torch.nn.Parameter(
                torch.ones(num_experts, dtype=torch.float32), requires_grad=False
            )
            layer.register_parameter("w13_input_scale", w13_input_scale)
            set_weight_attrs(w13_input_scale, extra_weight_attrs)

            w2_input_scale = torch.nn.Parameter(
                torch.ones(num_experts, dtype=torch.float32), requires_grad=False
            )
            layer.register_parameter("w2_input_scale", w2_input_scale)
            set_weight_attrs(w2_input_scale, extra_weight_attrs)

        else:
            layer.w13_input_scale = None
            layer.w2_input_scale = None

    def process_weights_after_loading(self, layer: Module) -> None:
        if _is_hip and _use_hip_int4:
            self.process_weights_hip_int4(layer)
            return

        # Block quant doesn't need to process weights after loading
        if self.block_quant:
            # If ROCm, normalize the weights and scales to e4m3fnuz
            if _is_fp8_fnuz:
                # activation_scheme: dynamic
                w13_weight, w13_weight_scale, _ = normalize_e4m3fn_to_e4m3fnuz(
                    weight=layer.w13_weight,
                    weight_scale=layer.w13_weight_scale_inv,
                    input_scale=None,
                )
                w2_weight, w2_weight_scale, _ = normalize_e4m3fn_to_e4m3fnuz(
                    weight=layer.w2_weight,
                    weight_scale=layer.w2_weight_scale_inv,
                    input_scale=None,
                )
                # Reset the parameter
                layer.w13_weight = torch.nn.Parameter(w13_weight, requires_grad=False)
                layer.w13_weight_scale_inv = torch.nn.Parameter(
                    w13_weight_scale, requires_grad=False
                )
                layer.w13_input_scale = None
                layer.w2_weight = torch.nn.Parameter(w2_weight, requires_grad=False)
                layer.w2_weight_scale_inv = torch.nn.Parameter(
                    w2_weight_scale, requires_grad=False
                )
                layer.w2_input_scale = None

            if _use_aiter:
                # Pre-shuffle weights
                layer.w13_weight.data = shuffle_weight(
                    layer.w13_weight.contiguous(), (16, 16)
                )
                layer.w2_weight.data = shuffle_weight(
                    layer.w2_weight.contiguous(), (16, 16)
                )

            if _is_cpu:
                assert (
                    _is_cpu_amx_available
                ), "Fp8MoEMethod on CPU requires that CPU has AMX support"
                _amx_process_weight_after_loading(layer, ["w13_weight", "w2_weight"])

            return

        # If checkpoint is fp16 or bfloat16, quantize in place.
        if not self.quant_config.is_checkpoint_fp8_serialized:
            # If ROCm, fp8_dtype will be float8_e4m3fnuz (MI300x HW)
            w13_weight = torch.empty_like(layer.w13_weight.data, dtype=fp8_dtype)
            w2_weight = torch.empty_like(layer.w2_weight.data, dtype=fp8_dtype)

            # Re-initialize w13_scale because we directly quantize
            # merged w13 weights and generate a single scaling factor.
            layer.w13_weight_scale = torch.nn.Parameter(
                torch.ones(
                    layer.num_local_experts,
                    dtype=torch.float32,
                    device=w13_weight.device,
                ),
                requires_grad=False,
            )
            for expert in range(layer.num_local_experts):
                w13_weight[expert, :, :], layer.w13_weight_scale[expert] = (
                    scaled_fp8_quant(layer.w13_weight.data[expert, :, :])
                )
                w2_weight[expert, :, :], layer.w2_weight_scale[expert] = (
                    scaled_fp8_quant(layer.w2_weight.data[expert, :, :])
                )
            layer.w13_weight = torch.nn.Parameter(w13_weight, requires_grad=False)
            layer.w2_weight = torch.nn.Parameter(w2_weight, requires_grad=False)

            if _is_hip:
                self.process_weights_hip_scale_padding(layer)
            return

        # If checkpoint is fp8, we need to handle that the
        # MoE kernels require single activation scale and single weight
        # scale for w13 per expert.
        else:
            # Fp8 moe kernels require a single activation scale.
            # We take the max of all the scales in case they differ.
            if self.quant_config.activation_scheme == "static":
                if layer.w13_input_scale is None or layer.w2_input_scale is None:
                    raise ValueError(
                        "QuantConfig has static quantization, but found "
                        "activation scales are None."
                    )
                if not all_close_1d(layer.w13_input_scale) or not all_close_1d(
                    layer.w2_input_scale
                ):
                    print_warning_once(
                        "Found input_scales that are not equal for "
                        "fp8 MoE layer. Using the maximum across experts "
                        "for each layer. "
                    )
                layer.w13_input_scale = torch.nn.Parameter(
                    layer.w13_input_scale.max(), requires_grad=False
                )
                layer.w2_input_scale = torch.nn.Parameter(
                    layer.w2_input_scale.max(), requires_grad=False
                )

            # If ROCm, normalize the weights and scales to e4m3fnuz
            if _is_fp8_fnuz:
                # Normalize the weights and scales
                w13_weight, w13_weight_scale, w13_input_scale = (
                    normalize_e4m3fn_to_e4m3fnuz(
                        layer.w13_weight, layer.w13_weight_scale, layer.w13_input_scale
                    )
                )
                w2_weight, w2_weight_scale, w2_input_scale = (
                    normalize_e4m3fn_to_e4m3fnuz(
                        layer.w2_weight, layer.w2_weight_scale, layer.w2_input_scale
                    )
                )
                # Reset the parameter
                layer.w13_weight = torch.nn.Parameter(w13_weight, requires_grad=False)
                layer.w13_weight_scale = torch.nn.Parameter(
                    w13_weight_scale, requires_grad=False
                )
                if w13_input_scale is not None:
                    layer.w13_input_scale = torch.nn.Parameter(
                        w13_input_scale, requires_grad=False
                    )
                layer.w2_weight = torch.nn.Parameter(w2_weight, requires_grad=False)
                layer.w2_weight_scale = torch.nn.Parameter(
                    w2_weight_scale, requires_grad=False
                )
                if w2_input_scale is not None:
                    layer.w2_input_scale = torch.nn.Parameter(
                        w2_input_scale, requires_grad=False
                    )
            # Fp8 moe kernel needs single weight scale for w13 per expert.
            # We take the max then dequant and requant each expert.
            assert layer.w13_weight_scale is not None
            shard_size = layer.intermediate_size_per_partition
            max_w13_scales = layer.w13_weight_scale.max(dim=1).values
            for expert_id in range(layer.num_local_experts):
                start = 0
                for shard_id in range(2):
                    dq_weight = per_tensor_dequantize(
                        layer.w13_weight[expert_id][start : start + shard_size, :],
                        layer.w13_weight_scale[expert_id][shard_id],
                    )
                    (
                        layer.w13_weight[expert_id][start : start + shard_size, :],
                        _,
                    ) = scaled_fp8_quant(dq_weight, max_w13_scales[expert_id])
                    start += shard_size

            layer.w13_weight_scale = torch.nn.Parameter(
                max_w13_scales, requires_grad=False
            )

            if _is_hip:
                self.process_weights_hip_scale_padding(layer)
            return

    def process_weights_hip_int4(self, layer: Module):
        # TODO: _use_aiter: add after triton kernel added
        # INT4-FP8 (INT4 MoE Weight, FP8 Compute)
        # Weight Permutation
        layer.w13_weight = torch.nn.Parameter(
            shuffle_weight(layer.w13_weight.data, (16, 16)),
            requires_grad=False,
        )
        torch.cuda.empty_cache()
        layer.w2_weight = torch.nn.Parameter(
            shuffle_weight(layer.w2_weight.data, (16, 16)),
            requires_grad=False,
        )
        torch.cuda.empty_cache()

        # INT4-FP8 : offset INT4 w13_weight_scale1 to single w13_weight_scale
        # Fp8 moe kernel needs single fp8 w13_weight_scale for w13 per expert.
        # We won't do requant each expert's fp8 weight (not direct available),
        # instead we adjust half of INT4 w13_weight_scale1 numbers
        assert layer.w13_weight_scale is not None
        shard_size = layer.intermediate_size_per_partition
        max_w13_scales = layer.w13_weight_scale.max(dim=1).values
        for expert_id in range(layer.num_local_experts):
            start = 0
            max_w13_scale_fp8 = max_w13_scales[expert_id]
            for shard_id in range(2):
                if layer.w13_weight_scale[expert_id][shard_id] != max_w13_scale_fp8:
                    int4_rescale = (
                        layer.w13_weight_scale[expert_id][shard_id] / max_w13_scale_fp8
                    )
                    layer.w13_weight_scale1[expert_id][
                        start : start + shard_size
                    ] *= int4_rescale
                start += shard_size

        layer.w13_weight_scale = torch.nn.Parameter(max_w13_scales, requires_grad=False)

        # special hack to asm_moe, which takes (weight_scale1 * weight_scale) as post GEMM scaling
        # optimal design - shall apply per-column weight_scale1 before GEMM, and weight_scale post
        for expert_id in range(layer.num_local_experts):
            layer.w13_weight_scale1[expert_id] *= max_w13_scales[expert_id]
            layer.w2_weight_scale1[expert_id] *= layer.w2_weight_scale[expert_id]

    def process_weights_hip_scale_padding(self, layer: Module):
        from sglang.srt.layers.moe.fused_moe_triton.fused_moe import (
            padding_size,  # Avoid circular import
        )

        if _use_aiter:
            layer.w13_weight = torch.nn.Parameter(
                shuffle_weight(layer.w13_weight.data, (16, 16)),
                requires_grad=False,
            )
            torch.cuda.empty_cache()
            layer.w2_weight = torch.nn.Parameter(
                shuffle_weight(layer.w2_weight.data, (16, 16)),
                requires_grad=False,
            )
            torch.cuda.empty_cache()

            # ROCm (_use_aiter): using column-wise scaling
            layer.w13_weight_scale1 *= layer.w13_weight_scale.unsqueeze(-1)
            layer.w2_weight_scale1 *= layer.w2_weight_scale.unsqueeze(-1)
        elif get_bool_env_var("SGLANG_MOE_PADDING"):
            # If ROCm, apply weight padding (min. Mem channel contention) only if set
            layer.w13_weight = torch.nn.Parameter(
                F.pad(layer.w13_weight.data, (0, padding_size), "constant", 0),
                requires_grad=False,
            )
            torch.cuda.empty_cache()
            layer.w2_weight = torch.nn.Parameter(
                F.pad(layer.w2_weight.data, (0, padding_size), "constant", 0),
                requires_grad=False,
            )
            torch.cuda.empty_cache()

    def create_moe_runner(
        self, layer: torch.nn.Module, moe_runner_config: MoeRunnerConfig
    ):
        self.moe_runner_config = moe_runner_config
        self.runner = MoeRunner(MoeRunnerBackend.TRITON, moe_runner_config)

    def apply(
        self,
        layer: torch.nn.Module,
        dispatch_output: DispatchOutput,
    ) -> CombineInput:

        from sglang.srt.layers.moe.token_dispatcher import StandardCombineInput

        x = dispatch_output.hidden_states
        topk_output = dispatch_output.topk_output
        moe_runner_config = self.moe_runner_config

        if use_intel_amx_backend(layer):
            from sglang.srt.layers.moe.topk import apply_topk_weights_cpu

            topk_weights, topk_ids, _ = topk_output
            x, topk_weights = apply_topk_weights_cpu(
                moe_runner_config.apply_router_weight_on_input, topk_weights, x
            )

            output = torch.ops.sgl_kernel.fused_experts_cpu(
                x,
                layer.w13_weight,
                layer.w2_weight,
                topk_weights,
                topk_ids,
                False,  # inplace See [Note] inplace should be False in fused_experts.
                False,  # use_int8_w8a8
                True,  # use_fp8_w8a16
                layer.w13_weight_scale_inv,  # w1_scale
                layer.w2_weight_scale_inv,  # w2_scale
                self.quant_config.weight_block_size,  # block_size
                None,  # a1_scale
                None,  # a2_scale
                True,  # is_vnni
            )
            return StandardCombineInput(hidden_states=output)

        if _is_hip:
            ret = self.maybe_apply_hip_fused_experts(
                layer,
                x,
                topk_output,
                moe_runner_config.activation,
                moe_runner_config.no_combine,
            )
            if ret is not None:
                return StandardCombineInput(hidden_states=ret)

        if self.use_cutlass_fused_experts_fp8:
            from sglang.srt.layers.moe.cutlass_moe import cutlass_fused_experts_fp8

            topk_weights, topk_ids, _ = topk_output
            output = cutlass_fused_experts_fp8(
                x,
                layer.w13_weight.transpose(1, 2),
                layer.w2_weight.transpose(1, 2),
                layer.w13_weight_scale_inv.transpose(1, 2),
                layer.w2_weight_scale_inv.transpose(1, 2),
                topk_weights,
                topk_ids,
                self.ab_strides1,
                self.c_strides1,
                self.ab_strides2,
                self.c_strides2,
                self.workspace,
                self.a_ptr,
                self.b_ptr,
                self.out_ptr,
                self.a_scales_ptr,
                self.b_scales_ptr,
                self.expert_offsets,
                self.problem_sizes1,
                self.problem_sizes2,
                use_fp8_blockscale=True,
            )
            return StandardCombineInput(hidden_states=output)

        quant_info = TritonMoeQuantInfo(
            w13_weight=layer.w13_weight,
            w2_weight=layer.w2_weight,
            use_fp8_w8a8=True,
            w13_scale=(
                layer.w13_weight_scale_inv
                if self.block_quant
                else layer.w13_weight_scale
            ),
            w2_scale=(
                layer.w2_weight_scale_inv if self.block_quant else layer.w2_weight_scale
            ),
            a13_scale=layer.w13_input_scale,
            a2_scale=layer.w2_input_scale,
            block_shape=self.quant_config.weight_block_size,
        )
        return self.runner.run(dispatch_output, quant_info)

    def apply_with_router_logits(
        self,
        layer: torch.nn.Module,
        dispatch_output: StandardDispatchOutput,
    ) -> torch.Tensor:
        x = dispatch_output.hidden_states
        topk_output = dispatch_output.topk_output

        activation = self.moe_runner_config.activation
        routed_scaling_factor = self.moe_runner_config.routed_scaling_factor

        from flashinfer.fused_moe import trtllm_fp8_block_scale_moe

        from sglang.srt.layers.moe.topk import TopKOutputChecker

        assert TopKOutputChecker.format_is_bypassed(topk_output)
        router_logits = topk_output.router_logits
        topk_config = topk_output.topk_config
        assert (
            activation == "silu"
        ), "Only silu is supported for flashinfer blockscale fp8 moe"
        a_q, a_sf = per_token_group_quant_fp8(x, self.quant_config.weight_block_size[1])
        # NOTE: scales of hidden states have to be transposed!
        a_sf_t = a_sf.t().contiguous()

        assert (
            topk_config.num_expert_group is not None
            and topk_config.topk_group is not None
        ), "Current trtllm_fp8_block_scale_moe kernel does not support these two arguments as None"

        correction_bias = (
            None
            if topk_config.correction_bias is None
            else topk_config.correction_bias.to(x.dtype)
        )

        return trtllm_fp8_block_scale_moe(
            routing_logits=router_logits.to(torch.float32),
            routing_bias=correction_bias,
            hidden_states=a_q,
            hidden_states_scale=a_sf_t,
            gemm1_weights=layer.w13_weight,
            gemm1_weights_scale=layer.w13_weight_scale_inv,
            gemm2_weights=layer.w2_weight,
            gemm2_weights_scale=layer.w2_weight_scale_inv,
            num_experts=layer.num_experts,
            top_k=topk_config.top_k,
            n_group=topk_config.num_expert_group,
            topk_group=topk_config.topk_group,
            intermediate_size=layer.w2_weight.shape[2],
            local_expert_offset=layer.moe_ep_rank * layer.num_local_experts,
            local_num_experts=layer.num_local_experts,
            routed_scaling_factor=(
                routed_scaling_factor if routed_scaling_factor is not None else 1.0
            ),
            tile_tokens_dim=get_tile_tokens_dim(
                x.shape[0], topk_config.top_k, layer.num_experts
            ),
            routing_method_type=2,  # DeepSeek-styled routing method
            use_shuffled_weight=False,
        )

    def maybe_apply_hip_fused_experts(
        self,
        layer: torch.nn.Module,
        x: torch.Tensor,
        topk_output: TopKOutput,
        activation: str = "silu",
        no_combine: bool = False,
    ) -> Optional[torch.Tensor]:
        topk_weights, topk_ids, _ = topk_output
        if _use_hip_int4:
            # TODO: add triton kernel and add check _use_aiter
            assert not no_combine, f"{no_combine=} is not supported."
            return fused_moe(
                x,
                layer.w13_weight,
                layer.w2_weight,
                topk_weights,
                topk_ids,
                quant_type=QuantType.per_Token,
                w1_scale=layer.w13_weight_scale1,
                w2_scale=layer.w2_weight_scale1,
                activation=(
                    ActivationType.Silu if activation == "silu" else ActivationType.Gelu
                ),
            )

        if _use_aiter:
            assert not no_combine, f"{no_combine=} is not supported."
            if self.block_quant:
                return fused_moe(
                    x,
                    layer.w13_weight,
                    layer.w2_weight,
                    topk_weights,
                    topk_ids,
                    w1_scale=layer.w13_weight_scale_inv,
                    w2_scale=layer.w2_weight_scale_inv,
                    quant_type=QuantType.per_128x128,
                    activation=(
                        ActivationType.Silu
                        if activation == "silu"
                        else ActivationType.Gelu
                    ),
                    expert_mask=None,
                )
            else:
                return fused_moe(
                    x,
                    layer.w13_weight,
                    layer.w2_weight,
                    topk_weights,
                    topk_ids,
                    quant_type=QuantType.per_Token,
                    w1_scale=layer.w13_weight_scale1,
                    w2_scale=layer.w2_weight_scale1,
                    activation=(
                        ActivationType.Silu
                        if activation == "silu"
                        else ActivationType.Gelu
                    ),
                )
        return None


class Fp8KVCacheMethod(BaseKVCacheMethod):
    """
    Supports loading kv-cache scaling factors from FP8 checkpoints.
    """

    def __init__(self, quant_config: Fp8Config):
        super().__init__(quant_config)
