Sync from v0.13

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2026-01-19 10:38:50 +08:00
parent b2ef04d792
commit 5aef6c175a
3714 changed files with 854317 additions and 89342 deletions

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@@ -1,22 +1,69 @@
# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
from abc import ABC, abstractmethod
from dataclasses import dataclass, fields
from typing import (Any, Dict, Generic, List, Optional, Set, Tuple, Type,
TypeVar)
from typing import TYPE_CHECKING, ClassVar, Generic, Protocol, TypeVar, get_args
import torch
if TYPE_CHECKING:
from vllm.config.cache import CacheDType
from vllm.model_executor.layers.linear import ColumnParallelLinear
from vllm.model_executor.layers.quantization.utils.quant_utils import QuantKey
from vllm.platforms.interface import DeviceCapability
from vllm.v1.attention.backends.utils import KVCacheLayoutType
class AttentionType:
"""
Attention type.
Use string to be compatible with `torch.compile`.
"""
DECODER = "decoder"
"""Decoder attention between previous layer Q/K/V."""
ENCODER = "encoder"
"""Encoder attention between previous layer Q/K/V for encoder-decoder."""
ENCODER_ONLY = "encoder_only"
"""Encoder attention between previous layer Q/K/V."""
ENCODER_DECODER = "encoder_decoder"
"""Attention between dec. Q and enc. K/V for encoder-decoder."""
class MultipleOf:
base: int
def __init__(self, base: int):
self.base = base
class AttentionBackend(ABC):
"""Abstract class for attention backends."""
# For some attention backends, we allocate an output tensor before
# calling the custom op. When piecewise cudagraph is enabled, this
# makes sure the output tensor is allocated inside the cudagraph.
accept_output_buffer: bool = False
supported_dtypes: ClassVar[list[torch.dtype]] = [torch.float16, torch.bfloat16]
supported_kv_cache_dtypes: ClassVar[list["CacheDType"]] = ["auto"]
@staticmethod
def get_supported_kernel_block_sizes() -> list[int | MultipleOf]:
return [MultipleOf(1)]
@staticmethod
@abstractmethod
def get_impl_cls() -> Type["AttentionImpl"]:
def get_name() -> str:
raise NotImplementedError
@staticmethod
@abstractmethod
def make_metadata(*args, **kwargs) -> "AttentionMetadataPerStage":
def get_impl_cls() -> type["AttentionImpl"]:
raise NotImplementedError
@staticmethod
@abstractmethod
def get_builder_cls(): # -> Type["AttentionMetadataBuilder"]:
raise NotImplementedError
@staticmethod
@@ -26,95 +73,212 @@ class AttentionBackend(ABC):
block_size: int,
num_kv_heads: int,
head_size: int,
) -> Tuple[int, ...]:
cache_dtype_str: str = "auto",
) -> tuple[int, ...]:
raise NotImplementedError
@staticmethod
@abstractmethod
def swap_blocks(
src_kv_cache: torch.Tensor,
dst_kv_cache: torch.Tensor,
src_to_dst: Dict[int, int],
) -> None:
def get_kv_cache_stride_order(
include_num_layers_dimension: bool = False,
) -> tuple[int, ...]:
"""
Get the physical (memory layout) ordering of the kv cache dimensions.
e.g. if the KV cache shape is
[2, num_blocks, block_size, num_heads, head_size],
and get_kv_cache_stride_order returns (1, 3, 0, 2, 4) then the physical
ordering of dimensions is
[num_blocks, num_heads, 2, block_size, head_size].
If this function is unimplemented / raises NotImplementedError,
the physical layout of the KV cache will match the logical shape.
Args:
include_num_layers_dimension: if True, includes an additional
num_layers dimension, which is assumed to be prepended
to the logical KV cache shape.
With the above example, a return value (2, 4, 0, 1, 3, 5)
corresponds to
[num_blocks, num_heads, num_layers, 2, block_size, head_size].
If an additional dimension is NOT included in the returned
tuple, the physical layout will not include a layers dimension.
Returns:
A tuple of ints which is a permutation of range(len(shape)).
"""
raise NotImplementedError
@staticmethod
@abstractmethod
def copy_blocks(
kv_caches: List[torch.Tensor],
src_to_dists: Dict[int, List[int]],
) -> None:
raise NotImplementedError
@classmethod
def full_cls_name(cls) -> tuple[str, str]:
return (cls.__module__, cls.__qualname__)
@classmethod
def get_supported_head_sizes(cls) -> list[int]:
return []
@dataclass
class AttentionMetadataPerStage:
"""Attention metadata for a specific stage. I.e., prefill or decode."""
@classmethod
def supports_head_size(cls, head_size: int) -> bool:
supported_head_sizes = cls.get_supported_head_sizes()
return (not supported_head_sizes) or head_size in supported_head_sizes
def asdict_zerocopy(self,
skip_fields: Optional[Set[str]] = None
) -> Dict[str, Any]:
"""Similar to dataclasses.asdict, but avoids deepcopying."""
if skip_fields is None:
skip_fields = set()
# Note that if we add dataclasses as fields, they will need
# similar handling.
return {
field.name: getattr(self, field.name)
for field in fields(self) if field.name not in skip_fields
}
@classmethod
def supports_dtype(cls, dtype: torch.dtype) -> bool:
return dtype in cls.supported_dtypes
@classmethod
def supports_kv_cache_dtype(cls, kv_cache_dtype: "CacheDType | None") -> bool:
if kv_cache_dtype is None:
return True
return (not cls.supported_kv_cache_dtypes) or (
kv_cache_dtype in cls.supported_kv_cache_dtypes
)
T = TypeVar("T", bound=AttentionMetadataPerStage)
@classmethod
def supports_block_size(cls, block_size: int | None) -> bool:
from vllm.config.cache import BlockSize
if block_size is None:
return True
@dataclass
class AttentionMetadata(Generic[T]):
"""Attention metadata for prefill and decode batched together."""
# Total number of prefill requests.
num_prefills: int
# Number of prefill tokens.
num_prefill_tokens: int
# Number of decode tokens. Note that it is equivalent to the number of
# decode requests.
num_decode_tokens: int
# The attention metadata for prefill requests in a batch.
# None if there's no prefill requests in a batch.
prefill_metadata: Optional[T]
# The attention metadata for decode requests in a batch.
# None if there's no decode requests in a batch.
decode_metadata: Optional[T]
# (num_tokens,). The indices of the token slots that input tokens will be
# stored into. E.g., if `slot_mapping` is [35, 2, 17] and the block size
# is 16, the three tokens are stored in the 3rd slot in block 2, 2nd slot
# in block 0, and 1st slot in block 1, respectively.
slot_mapping: torch.Tensor
# The kv cache's data type.
kv_cache_dtype: str
valid_sizes = get_args(BlockSize)
if block_size not in valid_sizes:
return False
def __post_init__(self):
if self.num_prefill_tokens > 0:
assert self.num_prefills > 0
assert self.prefill_metadata is not None
if self.num_decode_tokens > 0:
assert self.decode_metadata is not None
supported_kernel_block_sizes = cls.get_supported_kernel_block_sizes()
if not supported_kernel_block_sizes:
return True
for supported_size in supported_kernel_block_sizes:
if isinstance(supported_size, MultipleOf):
supported_size = supported_size.base
# With hybrid_blocks feature, the framework-level block size
# only needs to be a multiple of the kernel's requirement,
# even if the kernel requires a fixed block_size.
if block_size % supported_size == 0:
return True
return False
class AttentionImpl(ABC):
@classmethod
def is_mla(cls) -> bool:
return False
@abstractmethod
def __init__(
self,
num_heads: int,
@classmethod
def supports_sink(cls) -> bool:
return False
@classmethod
def supports_mm_prefix(cls) -> bool:
return False
@classmethod
def is_sparse(cls) -> bool:
return False
@classmethod
def supports_attn_type(cls, attn_type: str) -> bool:
"""Check if backend supports a given attention type.
By default, only supports decoder attention.
Backends should override this to support other attention types.
"""
return attn_type == AttentionType.DECODER
@classmethod
def supports_compute_capability(cls, capability: "DeviceCapability") -> bool:
return True
@classmethod
def supports_combination(
cls,
head_size: int,
scale: float,
num_kv_heads: Optional[int] = None,
alibi_slopes: Optional[List[float]] = None,
sliding_window: Optional[int] = None,
) -> None:
raise NotImplementedError
dtype: torch.dtype,
kv_cache_dtype: "CacheDType | None",
block_size: int | None,
use_mla: bool,
has_sink: bool,
use_sparse: bool,
device_capability: "DeviceCapability",
) -> str | None:
return None
@classmethod
def validate_configuration(
cls,
head_size: int,
dtype: torch.dtype,
kv_cache_dtype: "CacheDType | None",
block_size: int | None,
use_mla: bool,
has_sink: bool,
use_sparse: bool,
use_mm_prefix: bool,
device_capability: "DeviceCapability",
attn_type: str,
) -> list[str]:
invalid_reasons = []
if not cls.supports_head_size(head_size):
invalid_reasons.append("head_size not supported")
if not cls.supports_dtype(dtype):
invalid_reasons.append("dtype not supported")
if not cls.supports_kv_cache_dtype(kv_cache_dtype):
invalid_reasons.append("kv_cache_dtype not supported")
if not cls.supports_block_size(block_size):
invalid_reasons.append("block_size not supported")
if use_mm_prefix and not cls.supports_mm_prefix():
invalid_reasons.append(
"partial multimodal token full attention not supported"
)
if use_mla != cls.is_mla():
if use_mla:
invalid_reasons.append("MLA not supported")
else:
invalid_reasons.append("non-MLA not supported")
if has_sink and not cls.supports_sink():
invalid_reasons.append("sink setting not supported")
if use_sparse != cls.is_sparse():
if use_sparse:
invalid_reasons.append("sparse not supported")
else:
invalid_reasons.append("non-sparse not supported")
if not cls.supports_compute_capability(device_capability):
invalid_reasons.append("compute capability not supported")
if not cls.supports_attn_type(attn_type):
invalid_reasons.append(f"attention type {attn_type} not supported")
combination_reason = cls.supports_combination(
head_size,
dtype,
kv_cache_dtype,
block_size,
use_mla,
has_sink,
use_sparse,
device_capability,
)
if combination_reason is not None:
invalid_reasons.append(combination_reason)
return invalid_reasons
@classmethod
def get_required_kv_cache_layout(cls) -> "KVCacheLayoutType | None":
return None
class AttentionMetadata:
pass
T = TypeVar("T", bound=AttentionMetadata)
class AttentionLayer(Protocol):
_q_scale: torch.Tensor
_k_scale: torch.Tensor
_v_scale: torch.Tensor
_q_scale_float: float
_k_scale_float: float
_v_scale_float: float
_prob_scale: torch.Tensor
@abstractmethod
def forward(
self,
query: torch.Tensor,
@@ -122,6 +286,158 @@ class AttentionImpl(ABC):
value: torch.Tensor,
kv_cache: torch.Tensor,
attn_metadata: AttentionMetadata,
kv_scale: float,
) -> torch.Tensor: ...
class AttentionImpl(ABC, Generic[T]):
# Whether the attention impl can return the softmax lse for decode.
# Some features like decode context parallelism require the softmax lse.
can_return_lse_for_decode: bool = False
# Whether the attention impl supports Prefill Context Parallelism.
supports_pcp: bool = False
# Whether the attention impl(or ops) supports MTP
# when cp_kv_cache_interleave_size > 1
supports_mtp_with_cp_non_trivial_interleave_size: bool = False
# some attention backends might not always want to return lse
# even if they can return lse (for efficiency reasons)
need_to_return_lse_for_decode: bool = False
# Whether this attention implementation supports pre-quantized query input.
# When True, the attention layer will quantize queries before passing them
# to this backend, allowing torch.compile to fuse the quantization with
# previous operations. This is typically supported when using FP8 KV cache
# with compatible attention kernels (e.g., TRT-LLM).
# Subclasses should set this in __init__.
# TODO add support to more backends:
# https://github.com/vllm-project/vllm/issues/25584
supports_quant_query_input: bool = False
dcp_world_size: int
dcp_rank: int
pcp_world_size: int
pcp_rank: int
total_cp_world_size: int
total_cp_rank: int
def __new__(cls, *args, **kwargs):
# use __new__ so that all subclasses will call this
self = super().__new__(cls)
try:
from vllm.distributed.parallel_state import get_dcp_group
self.dcp_world_size = get_dcp_group().world_size
self.dcp_rank = get_dcp_group().rank_in_group
except AssertionError:
# DCP might not be initialized in testing
self.dcp_world_size = 1
self.dcp_rank = 0
try:
from vllm.distributed.parallel_state import get_pcp_group
self.pcp_world_size = get_pcp_group().world_size
self.pcp_rank = get_pcp_group().rank_in_group
except AssertionError:
self.pcp_world_size = 1
self.pcp_rank = 0
self.total_cp_world_size = self.pcp_world_size * self.dcp_world_size
self.total_cp_rank = self.pcp_rank * self.dcp_world_size + self.dcp_rank
self.need_to_return_lse_for_decode = (
self.dcp_world_size > 1 and self.can_return_lse_for_decode
)
return self
@abstractmethod
def __init__(
self,
num_heads: int,
head_size: int,
scale: float,
num_kv_heads: int | None = None,
alibi_slopes: list[float] | None = None,
sliding_window: int | None = None,
kv_cache_dtype: str = "auto",
logits_soft_cap: float | None = None,
attn_type: str = AttentionType.DECODER,
kv_sharing_target_layer_name: str | None = None,
) -> None:
raise NotImplementedError
@abstractmethod
def forward(
self,
layer: AttentionLayer,
query: torch.Tensor,
key: torch.Tensor,
value: torch.Tensor,
kv_cache: torch.Tensor,
attn_metadata: T,
output: torch.Tensor | None = None,
output_scale: torch.Tensor | None = None,
output_block_scale: torch.Tensor | None = None,
) -> torch.Tensor:
raise NotImplementedError
def fused_output_quant_supported(self, quant_key: "QuantKey"):
"""
Does this attention implementation support fused output quantization.
This is used by the AttnFusionPass to only fuse output quantization
onto implementations that support it.
:param quant_key: QuantKey object that describes the quantization op
:return: is fusion supported for this type of quantization
"""
return False
def process_weights_after_loading(self, act_dtype: torch.dtype):
pass
class MLAAttentionImpl(AttentionImpl[T], Generic[T]):
@abstractmethod
def __init__(
self,
num_heads: int,
head_size: int,
scale: float,
num_kv_heads: int,
alibi_slopes: list[float] | None,
sliding_window: int | None,
kv_cache_dtype: str,
logits_soft_cap: float | None,
attn_type: str,
kv_sharing_target_layer_name: str | None,
# MLA Specific Arguments
q_lora_rank: int | None,
kv_lora_rank: int,
qk_nope_head_dim: int,
qk_rope_head_dim: int,
qk_head_dim: int,
v_head_dim: int,
kv_b_proj: "ColumnParallelLinear",
indexer: object | None = None,
) -> None:
raise NotImplementedError
@abstractmethod
def forward(
self,
layer: AttentionLayer,
hidden_states_or_cq: torch.Tensor,
kv_c_normed: torch.Tensor,
k_pe: torch.Tensor,
kv_cache: torch.Tensor,
attn_metadata: T,
output: torch.Tensor | None = None,
output_scale: torch.Tensor | None = None,
output_block_scale: torch.Tensor | None = None,
) -> torch.Tensor:
raise NotImplementedError
def is_quantized_kv_cache(kv_cache_dtype: str) -> bool:
return kv_cache_dtype != "auto"