277 lines
10 KiB
Python
277 lines
10 KiB
Python
# SPDX-License-Identifier: Apache-2.0
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# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
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import inspect
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from abc import ABC, abstractmethod
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from typing import TYPE_CHECKING, Any
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import regex as re
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import torch
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from torch import nn
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from transformers import PretrainedConfig
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if TYPE_CHECKING:
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from vllm.model_executor.layers.quantization import QuantizationMethods
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from vllm.model_executor.models.utils import WeightsMapper
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else:
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QuantizationMethods = str
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class QuantizeMethodBase(ABC):
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"""Base class for different quantized methods."""
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uses_meta_device: bool = False
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"""
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Whether this method creates weights on meta device for online quantization.
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When True, weights are created on meta device and quantized layer-wise
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in process_weights_after_loading, reducing peak memory during loading.
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"""
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@abstractmethod
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def create_weights(
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self, layer: torch.nn.Module, *weight_args, **extra_weight_attrs
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):
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"""Create weights for a layer.
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The weights will be set as attributes of the layer."""
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raise NotImplementedError
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@abstractmethod
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def apply(self, layer: torch.nn.Module, *args, **kwargs) -> torch.Tensor:
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"""Apply the weights in layer to the input tensor.
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Expects create_weights to have been called before on the layer."""
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raise NotImplementedError
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# Not required functions
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def embedding(self, layer: torch.nn.Module, *args, **kwargs) -> torch.Tensor:
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"""Gather embeddings in the layer based on indices in the input tensor.
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Expects create_weights to have been called before on the layer."""
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raise NotImplementedError
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# Not required functions
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def tie_weights(self, layer: torch.nn.Module, embed_tokens: torch.nn.Module):
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"""Tie ``layer``'s weight to ``embed_tokens``' weight.
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The default shares the weight tensor, which is the standard behavior for
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tied word embeddings and matches what ``ParallelLMHead.tie_weights`` did
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directly before quantization methods became responsible for it.
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Quantization methods that need special weight handling (e.g. repacked
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weights) override this.
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Expects create_weights to have been called before on the layer."""
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layer.weight = embed_tokens.weight
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return layer
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def process_weights_after_loading(self, layer: nn.Module) -> None:
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"""Process the weight after loading.
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This can be used for example, to transpose weights for computation.
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"""
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return
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def method_has_implemented_embedding(method_class: type[QuantizeMethodBase]) -> bool:
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"""
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Not all quant methods have embedding implemented, so we need to check that
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it exists for our given method. We check this by making sure the function
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has been changed from the base implementation.
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"""
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base_embedding = inspect.getattr_static(QuantizeMethodBase, "embedding", None)
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class_embedding = inspect.getattr_static(method_class, "embedding", None)
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return class_embedding is not None and class_embedding is not base_embedding
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class QuantizationConfig(ABC):
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"""Base class for quantization configs."""
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_ignore_unexpected_suffixes = (
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".q_scale",
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".k_scale",
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".v_scale",
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".q_zero_point",
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".k_zero_point",
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".v_zero_point",
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)
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"""Suffixes of quantization parameters that may be present in the checkpoint but
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not in the model, and should be ignored if unexpected during loading. These are used
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after remapping, so should be in vLLM format (e.g. .q_scale, not .q.scale)."""
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def __init__(self):
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super().__init__()
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# mapping is updated by models as they initialize
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self.packed_modules_mapping: dict[str, list[str]] = dict()
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@abstractmethod
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def get_name(self) -> QuantizationMethods:
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"""Name of the quantization method."""
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raise NotImplementedError
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@abstractmethod
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def get_supported_act_dtypes(self) -> list[torch.dtype]:
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"""List of supported activation dtypes."""
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raise NotImplementedError
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@classmethod
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@abstractmethod
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def get_min_capability(cls) -> int:
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"""Minimum GPU capability to support the quantization method.
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E.g., 70 for Volta, 75 for Turing, 80 for Ampere.
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This requirement is due to the custom CUDA kernels used by the
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quantization method.
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"""
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raise NotImplementedError
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@staticmethod
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@abstractmethod
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def get_config_filenames() -> list[str]:
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"""List of filenames to search for in the model directory."""
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raise NotImplementedError
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@classmethod
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@abstractmethod
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def from_config(cls, config: dict[str, Any]) -> "QuantizationConfig":
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"""Create a config class from the model's quantization config."""
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raise NotImplementedError
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@classmethod
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def override_quantization_method(
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cls,
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hf_quant_cfg: dict[str, Any],
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user_quant: str | None,
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hf_config: Any = None,
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) -> QuantizationMethods | None:
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"""
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Detects if this quantization method can support a given checkpoint
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format by overriding the user specified quantization method --
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this method should only be overwritten by subclasses in exceptional
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circumstances.
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Args:
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hf_quant_cfg: The checkpoint's quantization config dict.
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user_quant: The user-specified quantization method string.
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hf_config: The HuggingFace model config object (e.g. for
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model_type checks). May be None if not available.
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"""
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return None
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@staticmethod
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def get_from_keys(config: dict[str, Any], keys: list[str]) -> Any:
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"""Get a value from the model's quantization config."""
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for key in keys:
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if key in config:
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return config[key]
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raise ValueError(
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f"Cannot find any of {keys} in the model's quantization config."
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)
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@staticmethod
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def get_from_keys_or(config: dict[str, Any], keys: list[str], default: Any) -> Any:
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"""Get an optional value from the model's quantization config."""
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try:
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return QuantizationConfig.get_from_keys(config, keys)
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except ValueError:
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return default
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@abstractmethod
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def get_quant_method(
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self, layer: torch.nn.Module, prefix: str
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) -> QuantizeMethodBase | None:
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"""Get the quantize method to use for the quantized layer.
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Args:
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layer: The layer for the quant method.
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prefix: The full name of the layer in the state dict
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Returns:
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The quantize method. None if the given layer doesn't support quant
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method.
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"""
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raise NotImplementedError
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@staticmethod
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def get_cache_scale_mapper() -> "WeightsMapper":
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"""Mapping from checkpoint KV-cache scale names to vLLM scale names.
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Returning a mapper here causes `AutoWeightsLoader` to apply it to the
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weight stream automatically; individual model `load_weights` methods
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do not need to know about KV-cache scales.
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"""
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from vllm.model_executor.models.utils import WeightsMapper
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orig_to_new_regex = {
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# Deprecated fused kv_scale -> attn.k_scale
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re.compile(r"\.kv_scale$"): r".attn.k_scale",
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# ModelOpt: .self_attn.{k,v}_proj.{k,v}_scale -> .self_attn.attn.*
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re.compile(r"\.self_attn\.[kv]_proj\.([kv])_scale$"): (
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r".self_attn.attn.\1_scale"
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),
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# Fused QKV / qkqkv proj: .self_attn.qk(qk)v_proj.{k,v}_scale -> attn
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re.compile(r"\.self_attn\.qk(?:qk)?v_proj\.([kv])_scale$"): (
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r".self_attn.attn.\1_scale"
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),
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# NemotronH: .mixer.{k,v}_proj.{k,v}_scale -> .mixer.attn.*
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re.compile(r"\.mixer\.[kv]_proj\.([kv])_scale$"): r".mixer.attn.\1_scale",
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# HYV3: .self_attn.q.scale -> .self_attn.attn.q_scale
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re.compile(r"\.self_attn\.q\.scale$"): r".self_attn.attn.q_scale",
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# HYV3: .self_attn.{k,v}_cache.scale -> .self_attn.attn.{k,v}_scale
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re.compile(r"\.self_attn\.([kv])_cache\.scale$"): (
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r".self_attn.attn.\1_scale"
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),
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# Default: .{q,k,v}_scale -> .attn.{q,k,v}_scale (unless already .attn)
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re.compile(r"(?<!\.attn)\.([qkv])_scale$"): r".attn.\1_scale",
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re.compile(r"(?<!\.attn)\.([qkv])_zero_point$"): r".attn.\1_zero_point",
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}
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return WeightsMapper(orig_to_new_regex=orig_to_new_regex)
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def apply_vllm_mapper( # noqa: B027
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self, hf_to_vllm_mapper: "WeightsMapper"
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):
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"""
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Interface for models to update module names referenced in
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quantization configs in order to reflect the vllm model structure
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Args:
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hf_to_vllm_mapper: maps from hf model structure (the assumed
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structure of the qconfig) to vllm model structure
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"""
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# TODO (@kylesayrs): add implementations for all subclasses
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pass
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def maybe_update_config( # noqa: B027
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self,
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model_name: str,
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hf_config: PretrainedConfig | None = None,
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revision: str | None = None,
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):
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"""
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Interface to update values after config initialization.
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Args:
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model_name: The name of the model
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hf_config: The Hugging Face config of the model
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revision: The revision of the model
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Returns:
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"""
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# TODO: revision is never passed currently in vllm.py,
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# but is used in subclasses, should we remove this parameter?
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pass
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def is_mxfp4_quant(self, prefix: str, layer: torch.nn.Module) -> bool:
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"""
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Determine if mxfp4 quantization will be used for this config.
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This allows hidden_size rounding to happen before moe_config creation
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without needing to instantiate quant_method first.
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Args:
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prefix: The layer prefix/name in the model
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layer: The layer module
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Returns:
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True if this config uses MXFP4 quantization, False otherwise
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"""
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return False
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