[5/N][Attention] Finish eliminating vllm/attention folder (#32064)

Signed-off-by: Matthew Bonanni <mbonanni@redhat.com>
This commit is contained in:
Matthew Bonanni
2026-01-27 10:02:51 -05:00
committed by GitHub
parent 1f3a2c2944
commit a608b4c6c2
151 changed files with 585 additions and 527 deletions

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# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
from vllm.model_executor.layers.attention.attention import Attention
from vllm.model_executor.layers.attention.chunked_local_attention import (
ChunkedLocalAttention,
)
from vllm.model_executor.layers.attention.cross_attention import CrossAttention
from vllm.model_executor.layers.attention.encoder_only_attention import (
EncoderOnlyAttention,
)
from vllm.model_executor.layers.attention.mla_attention import MLAAttention
from vllm.model_executor.layers.attention.mm_encoder_attention import MMEncoderAttention
from vllm.model_executor.layers.attention.static_sink_attention import (
StaticSinkAttention,
)
__all__ = [
"Attention",
"ChunkedLocalAttention",
"CrossAttention",
"EncoderOnlyAttention",
"MLAAttention",
"MMEncoderAttention",
"StaticSinkAttention",
]

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# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
from typing import TYPE_CHECKING
import torch
import torch.nn as nn
import vllm.envs as envs
from vllm.config import CacheConfig, get_current_vllm_config
from vllm.config.vllm import VllmConfig
from vllm.forward_context import ForwardContext, get_forward_context
from vllm.logger import init_logger
from vllm.model_executor.layers.attention.kv_transfer_utils import (
maybe_transfer_kv_layer,
)
from vllm.model_executor.layers.attention_layer_base import AttentionLayerBase
from vllm.model_executor.layers.batch_invariant import vllm_is_batch_invariant
from vllm.model_executor.layers.linear import (
UnquantizedLinearMethod,
)
from vllm.model_executor.layers.quantization import QuantizationConfig
from vllm.model_executor.layers.quantization.base_config import QuantizeMethodBase
from vllm.model_executor.layers.quantization.input_quant_fp8 import QuantFP8
from vllm.model_executor.layers.quantization.kv_cache import BaseKVCacheMethod
from vllm.model_executor.layers.quantization.utils.quant_utils import GroupShape
from vllm.platforms import current_platform
from vllm.utils.torch_utils import (
direct_register_custom_op,
kv_cache_dtype_str_to_dtype,
)
from vllm.v1.attention.backend import (
AttentionBackend,
AttentionType,
)
from vllm.v1.attention.backends.registry import AttentionBackendEnum
from vllm.v1.attention.selector import get_attn_backend
from vllm.v1.kv_cache_interface import (
FullAttentionSpec,
KVCacheSpec,
SlidingWindowSpec,
)
if TYPE_CHECKING:
from vllm.model_executor.layers.attention import MLAAttention
logger = init_logger(__name__)
def validate_kv_sharing_target(
current_layer_name, target_layer_name, static_forward_context
):
error_msg = (
f"Specified KV sharing target layer for {current_layer_name} "
f"is not valid: target layer {target_layer_name} "
)
if current_layer_name == target_layer_name:
raise ValueError(error_msg + "cannot be the same as the current layer.")
if target_layer_name not in static_forward_context:
from vllm.model_executor.models.utils import extract_layer_index
# If target layer name is not in the static fwd context, it means either
# a) the target layer does not come BEFORE the current layer, or
# b) the target layer is not an Attention layer that exists in the model
current_layer_idx = extract_layer_index(current_layer_name)
target_layer_idx = extract_layer_index(target_layer_name)
if current_layer_idx <= target_layer_idx:
raise ValueError(error_msg + "must come before the current layer.")
else:
raise ValueError(error_msg + "is not a valid Attention layer in the model.")
# Currently KV sharing is only supported between layers of the same type
target_layer_attn_type = static_forward_context[target_layer_name].attn_type
expected = static_forward_context[current_layer_name].attn_type
if target_layer_attn_type != expected:
raise ValueError(
error_msg + f"must be the same type as the current layer ({expected})."
)
def should_load_quant_weights(quant_method: QuantizeMethodBase | None) -> bool:
"""Returns whether the quantization method should load quantized weights."""
return quant_method is not None and not isinstance(
quant_method, UnquantizedLinearMethod
)
def set_default_quant_scales(layer: nn.Module, register_buffer: bool = False) -> None:
"""Sets default quantization scales for the layer."""
if register_buffer:
layer.register_buffer("_k_scale", torch.tensor(1.0, dtype=torch.float32))
layer.register_buffer("_v_scale", torch.tensor(1.0, dtype=torch.float32))
layer.register_buffer("_q_scale", torch.tensor(1.0, dtype=torch.float32))
layer.register_buffer("_prob_scale", torch.tensor(1.0, dtype=torch.float32))
else:
layer._k_scale.fill_(1.0)
layer._v_scale.fill_(1.0)
layer._q_scale.fill_(1.0)
layer._prob_scale.fill_(1.0)
# We also keep q/k/v_scale on host (cpu) memory for attention
# backends that require the scales to be on host instead of on device.
# e.g. Flashinfer
layer._q_scale_float = 1.0
layer._k_scale_float = 1.0
layer._v_scale_float = 1.0
layer._prob_scale_float = 1.0
# Initialize q/k/v range constants used by calc_kv_scales
layer.q_range = torch.tensor(envs.Q_SCALE_CONSTANT, dtype=torch.float32)
layer.k_range = torch.tensor(envs.K_SCALE_CONSTANT, dtype=torch.float32)
layer.v_range = torch.tensor(envs.V_SCALE_CONSTANT, dtype=torch.float32)
def _init_kv_cache_quant(
layer: nn.Module,
quant_config: QuantizationConfig | None,
prefix: str,
) -> None:
"""Initializes KV cache scaling factors and quantization method.
This helper function sets up the KV cache quantization attributes that are
shared between Attention and MLAAttention layers. It initializes scale
tensors for query, key, value, and probability, and configures the
quantization method if applicable.
Args:
layer: The attention layer instance to initialize.
quant_config: Optional quantization configuration.
prefix: Layer name prefix for quantization method lookup.
"""
quant_method = (
quant_config.get_quant_method(layer, prefix=prefix) if quant_config else None
)
# Note [Register q/k/v/prob scales in state dict]
# When calling model.to(device), only parameters/buffers in state dict are
# moved. If not registering q/k/v/prob scales in state dict, there would
# be an IMA error when a cuda kernel (e.g., quant_fp8) accesses the tensor
# on cpu.
# Registering in state dict means it interacts with weight loading. One edge
# case is when quant_method is None, or quant_method is UnquantizedLinearMethod
# (i.e., should_load_quant_weights(quant_method) == False).
# In this case, the checkpoint does not have the scales. We need to
# initialize the scales to 1.0 and update the scales after weight loading.
# This is espectially important when we load dummy weights first (providing
# wrong scales) and then load real weights (which misses scales and keeps the
# wrong scales from dummy load).
set_default_quant_scales(layer, register_buffer=True)
# The output scale on host memory. This should be the input scale of
# the quant op after this attention layer.
layer._o_scale_float = None
quant_method = (
quant_config.get_quant_method(layer, prefix=prefix) if quant_config else None
)
# See [Note: Register q/k/v/prob scales in state dict]
if should_load_quant_weights(quant_method):
assert isinstance(quant_method, BaseKVCacheMethod)
# TODO (mgoin): kv cache dtype should be specified in the FP8
# checkpoint config and become the "auto" behavior
if layer.kv_cache_dtype == "fp8_e5m2":
raise ValueError("fp8_e5m2 kv-cache is not supported with fp8 checkpoints.")
# If quantization is enabled, we make "k_scale" and "v_scale"
# parameters so that it can be loaded from the model checkpoint.
# The k/v_scale will then be converted back to native float32
# values after weight loading.
layer.quant_method = quant_method
layer.quant_method.create_weights(layer)
class Attention(nn.Module, AttentionLayerBase):
"""Attention layer.
This class takes query, key, and value tensors as input. The input tensors
can either contain prompt tokens or generation tokens.
The class does the following:
1. Store the input key and value tensors in the KV cache.
2. Perform (multi-head/multi-query/grouped-query) attention.
3. Return the output tensor.
"""
def __init__(
self,
num_heads: int,
head_size: int,
scale: float,
num_kv_heads: int | None = None,
alibi_slopes: list[float] | None = None,
use_alibi_sqrt: bool | None = None,
cache_config: CacheConfig | None = None,
quant_config: QuantizationConfig | None = None,
logits_soft_cap: float | None = None,
per_layer_sliding_window: int | None = None,
prefix: str = "",
attn_type: str = AttentionType.DECODER,
kv_sharing_target_layer_name: str | None = None,
attn_backend: type[AttentionBackend] | None = None,
head_size_v: int | None = None,
**extra_impl_args,
) -> None:
"""
The KV cache is stored inside this class and is accessed via
`self.kv_cache`.
"""
super().__init__()
if per_layer_sliding_window is not None:
# per-layer sliding window
sliding_window = per_layer_sliding_window
elif cache_config is not None:
# model-level sliding window
sliding_window = cache_config.sliding_window
else:
sliding_window = None
vllm_config = get_current_vllm_config()
if cache_config is not None:
kv_cache_dtype = cache_config.cache_dtype
block_size = cache_config.block_size
calculate_kv_scales = cache_config.calculate_kv_scales
else:
kv_cache_dtype = "auto"
block_size = 16
calculate_kv_scales = False
# llm-compressor mdls need to set cache_dtype to "fp8" manually.
if getattr(quant_config, "kv_cache_scheme", None) is not None:
kv_cache_dtype = "fp8"
calculate_kv_scales = False
if cache_config is not None:
cache_config.cache_dtype = "fp8"
cache_config.calculate_kv_scales = False
self.kv_cache_torch_dtype = kv_cache_dtype_str_to_dtype(
kv_cache_dtype, vllm_config.model_config
)
self.kv_cache_dtype = kv_cache_dtype
self.calculate_kv_scales = calculate_kv_scales
if num_kv_heads is None:
num_kv_heads = num_heads
assert num_heads % num_kv_heads == 0, (
f"num_heads ({num_heads}) is not divisible by num_kv_heads ({num_kv_heads})"
)
self.quant_config = quant_config
self.layer_name = prefix
self.num_heads = num_heads
self.head_size = head_size
self.head_size_v = self.head_size if head_size_v is None else head_size_v
self.num_kv_heads = num_kv_heads
self.sliding_window = sliding_window
self.has_sink = extra_impl_args.get("sinks") is not None
# NOTE: model_config may be None during certain tests
model_config = vllm_config.model_config
self.use_mm_prefix = model_config is not None and model_config.is_mm_prefix_lm
# During model initialization, the default dtype is set as the model
# weight and activation dtype.
dtype = torch.get_default_dtype()
if attn_backend is None:
self.attn_backend = get_attn_backend(
head_size,
dtype,
kv_cache_dtype,
block_size,
use_mla=False,
has_sink=self.has_sink,
use_mm_prefix=self.use_mm_prefix,
attn_type=attn_type,
)
else:
self.attn_backend = attn_backend
backend_supports_alibi_sqrt = self.attn_backend.supports_alibi_sqrt()
use_alibi_sqrt = use_alibi_sqrt if use_alibi_sqrt else False
if use_alibi_sqrt and not backend_supports_alibi_sqrt:
raise ValueError(
f"use_alibi_sqrt is not supported by backend "
f"{self.attn_backend.get_name()}."
)
self.use_alibi_sqrt = bool(use_alibi_sqrt)
if backend_supports_alibi_sqrt:
extra_impl_args["use_alibi_sqrt"] = self.use_alibi_sqrt
# prefix caching + batch invariance is currently not supported for
# FLASHINFER and TRITON_MLA.
if (
cache_config is not None
and cache_config.enable_prefix_caching
and vllm_is_batch_invariant()
and (
self.attn_backend.get_name() == "FLASHINFER"
or self.attn_backend.get_name() == "TRITON_MLA"
)
):
logger.warning_once(
"Disabling prefix caching for FLASHINFER/TRITON_MLA "
"with batch invariance, as it is not yet supported.",
scope="local",
)
cache_config.enable_prefix_caching = False
impl_cls = self.attn_backend.get_impl_cls()
self.impl = impl_cls(
num_heads,
head_size,
scale,
num_kv_heads,
alibi_slopes,
sliding_window,
kv_cache_dtype,
logits_soft_cap,
attn_type,
kv_sharing_target_layer_name,
**extra_impl_args,
)
self.backend = AttentionBackendEnum[self.attn_backend.get_name()]
self.dtype = dtype
# For cuda-alike (CUDA and ROCM) and cpu platforms, we control how
# torch.compile works by registering the attention as one giant
# opaque custom op. For other platforms, we directly call them
# and let torch.compile handle them.
self.use_direct_call = not current_platform.opaque_attention_op()
self.use_output = self.attn_backend.accept_output_buffer
compilation_config = vllm_config.compilation_config
if prefix in compilation_config.static_forward_context:
raise ValueError(f"Duplicate layer name: {prefix}")
compilation_config.static_forward_context[prefix] = self
self.attn_type = attn_type
if kv_sharing_target_layer_name is not None:
validate_kv_sharing_target(
prefix,
kv_sharing_target_layer_name,
compilation_config.static_forward_context,
)
self.kv_sharing_target_layer_name = kv_sharing_target_layer_name
# use a placeholder kv cache tensor during init, which will be replaced
# by bind_kv_cache
# this variable will not be accessed if use_direct_call is True
self.kv_cache = [
torch.tensor([])
for _ in range(vllm_config.parallel_config.pipeline_parallel_size)
]
# Initialize KV cache quantization attributes
_init_kv_cache_quant(self, quant_config, prefix)
# for attn backends supporting query quantization
self.query_quant = None
if self.impl.supports_quant_query_input and self.kv_cache_dtype.startswith(
"fp8"
):
is_per_head = (
hasattr(self, "q_scale") and self.q_scale.numel() == self.num_kv_heads
)
block_size = self.head_size * self.num_heads // self.num_kv_heads
self.query_quant = QuantFP8(
static=True,
group_shape=GroupShape(-1, block_size)
if is_per_head
else GroupShape.PER_TENSOR,
)
def forward(
self,
query: torch.Tensor,
key: torch.Tensor,
value: torch.Tensor,
# For some alternate attention backends like MLA the attention output
# shape does not match the query shape, so we optionally let the model
# definition specify the output tensor shape.
output_shape: torch.Size | None = None,
) -> torch.Tensor:
"""
The KV cache is stored inside this class and is accessed via
`self.kv_cache`.
Attention metadata (`attn_metadata`) is set using a context manager in
the model runner's `execute_model` method. It is accessed via forward
context using
`vllm.forward_context.get_forward_context().attn_metadata`.
"""
if self.calculate_kv_scales:
torch.ops.vllm.maybe_calc_kv_scales(query, key, value, self.layer_name)
output_dtype = query.dtype
if self.query_quant is not None:
# quantizing with a simple torch operation enables
# torch.compile to fuse this into previous ops
# which reduces overheads during decoding.
# Otherwise queries are quantized using custom ops
# which causes decoding overheads
assert self.kv_cache_dtype in {"fp8", "fp8_e4m3"}
# check if query quantization is supported
if self.impl.supports_quant_query_input:
query, _ = self.query_quant(query, self._q_scale)
if self.use_output:
if output_shape is None:
# Handle both 2D [num_tokens, hidden] and
# 3D [num_tokens, heads, head_dim] query
num_tokens = query.shape[0]
output_shape = torch.Size(
(num_tokens, self.num_heads * self.head_size_v)
)
output = torch.empty(output_shape, dtype=output_dtype, device=query.device)
hidden_size = output_shape[-1]
# Reshape the query, key, and value tensors.
# NOTE(woosuk): We do this outside the custom op to minimize the
# CPU overheads from the non-CUDA-graph regions.
query = query.view(-1, self.num_heads, self.head_size)
output = output.view(-1, self.num_heads, self.head_size_v)
if key is not None:
key = key.view(-1, self.num_kv_heads, self.head_size)
if value is not None:
value = value.view(-1, self.num_kv_heads, self.head_size_v)
if self.use_direct_call:
kv_cache_dummy_dep = None
if not self.attn_backend.forward_includes_kv_cache_update:
kv_cache_dummy_dep = unified_kv_cache_update(
key, value, self.layer_name
)
unified_attention_with_output(
query,
key,
value,
output,
self.layer_name,
kv_cache_dummy_dep=kv_cache_dummy_dep,
)
else:
kv_cache_dummy_dep = None
if not self.attn_backend.forward_includes_kv_cache_update and (
# torch can only dispatch custom op if a tensor is passed
key is not None or value is not None
):
kv_cache_dummy_dep = torch.ops.vllm.unified_kv_cache_update(
key, value, self.layer_name
)
torch.ops.vllm.unified_attention_with_output(
query,
key,
value,
output,
self.layer_name,
kv_cache_dummy_dep=kv_cache_dummy_dep,
)
return output.view(-1, hidden_size)
else:
assert self.attn_backend.forward_includes_kv_cache_update, (
"Split KV cache update not supported when output tensor not provided."
)
if self.use_direct_call:
return unified_attention(query, key, value, self.layer_name)
else:
return torch.ops.vllm.unified_attention(
query, key, value, self.layer_name
)
def calc_kv_scales(self, query, key, value):
self._q_scale.copy_(torch.abs(query).max() / self.q_range)
self._k_scale.copy_(torch.abs(key).max() / self.k_range)
self._v_scale.copy_(torch.abs(value).max() / self.v_range)
self._q_scale_float = self._q_scale.item()
self._k_scale_float = self._k_scale.item()
self._v_scale_float = self._v_scale.item()
# We only calculate the scales once
self.calculate_kv_scales = False
def extra_repr(self) -> str:
s = f"head_size={self.impl.head_size}" # type: ignore
s += f", num_heads={self.impl.num_heads}" # type: ignore
s += f", num_kv_heads={self.impl.num_kv_heads}" # type: ignore
s += f", scale={self.impl.scale}" # type: ignore
s += f", backend={self.impl.__class__.__name__}"
return s
def process_weights_after_loading(self, act_dtype: torch.dtype):
self.impl.process_weights_after_loading(act_dtype)
# If we should not load quant weights, we initialize the scales to 1.0
# as the default value. See [Note: Register q/k/v/prob scales in state dict]
# for more details.
quant_method = (
self.quant_config.get_quant_method(self, prefix=self.layer_name)
if self.quant_config
else None
)
if not should_load_quant_weights(quant_method):
set_default_quant_scales(self, register_buffer=False)
def get_attn_backend(self) -> type[AttentionBackend]:
return self.attn_backend
def get_kv_cache_spec(self, vllm_config: VllmConfig) -> KVCacheSpec:
# Block size may get updated after model loading, refresh it
block_size = vllm_config.cache_config.block_size
# Should not be called for enc-dec or encoder-only attention.
assert self.attn_type == AttentionType.DECODER
if self.sliding_window is not None:
assert not vllm_config.model_config.use_mla, (
"MLA is not supported for slidingwindow"
)
return SlidingWindowSpec(
block_size=block_size,
num_kv_heads=self.num_kv_heads,
head_size=self.head_size,
dtype=self.kv_cache_torch_dtype,
sliding_window=self.sliding_window,
)
else:
return FullAttentionSpec(
block_size=block_size,
num_kv_heads=self.num_kv_heads,
head_size=self.head_size,
head_size_v=self.head_size_v,
dtype=self.kv_cache_torch_dtype,
)
def maybe_calc_kv_scales(
query: torch.Tensor,
key: torch.Tensor,
value: torch.Tensor,
layer_name: str,
) -> None:
forward_context: ForwardContext = get_forward_context()
self = forward_context.no_compile_layers[layer_name]
# Only calculate if the layer's calculate_kv_scales flag is True
# This flag gets set to False after the first forward pass
if not self.calculate_kv_scales:
return
self.calc_kv_scales(query, key, value)
def maybe_calc_kv_scales_fake(
query: torch.Tensor,
key: torch.Tensor,
value: torch.Tensor,
layer_name: str,
) -> None:
return
direct_register_custom_op(
op_name="maybe_calc_kv_scales",
op_func=maybe_calc_kv_scales,
mutates_args=["query", "key", "value"],
fake_impl=maybe_calc_kv_scales_fake,
)
def get_attention_context(
layer_name: str,
) -> tuple[dict | object | None, "Attention | MLAAttention", torch.Tensor]:
"""Extract attention context for a given layer.
This helper function extracts the attention metadata, attention layer
instance, and KV cache tensor for a specific layer.
Args:
layer_name: The name/identifier of the attention layer.
Returns:
A tuple containing:
- attn_metadata: Attention metadata for this specific layer, or None if
no metadata available
- attn_layer: The attention layer instance (Attention or MLAAttention)
- kv_cache: The KV cache tensor for current virtual engine
Note: attn_metadata may be None, but attn_layer and kv_cache are always
extracted from the forward context.
"""
forward_context: ForwardContext = get_forward_context()
attn_metadata = forward_context.attn_metadata
if isinstance(attn_metadata, dict):
attn_metadata = attn_metadata[layer_name]
attn_layer = forward_context.no_compile_layers[layer_name]
kv_cache = attn_layer.kv_cache[forward_context.virtual_engine]
return attn_metadata, attn_layer, kv_cache
@maybe_transfer_kv_layer
def unified_attention(
query: torch.Tensor,
key: torch.Tensor,
value: torch.Tensor,
layer_name: str,
) -> torch.Tensor:
attn_metadata, self, kv_cache = get_attention_context(layer_name)
output = self.impl.forward(self, query, key, value, kv_cache, attn_metadata)
return output
def unified_attention_fake(
query: torch.Tensor,
key: torch.Tensor,
value: torch.Tensor,
layer_name: str,
) -> torch.Tensor:
return torch.empty_like(query).contiguous()
direct_register_custom_op(
op_name="unified_attention",
op_func=unified_attention,
fake_impl=unified_attention_fake,
)
def unified_kv_cache_update(
key: torch.Tensor,
value: torch.Tensor,
layer_name: str,
) -> torch.Tensor:
"""
Returns a dummy that is passed to unified_attention to signal a side effect and
the data dependency between them to ensure torch.compile preserves ordering.
"""
forward_context = get_forward_context()
attn_layer = forward_context.no_compile_layers[layer_name]
kv_cache = attn_layer.kv_cache[forward_context.virtual_engine]
slot_mapping = forward_context.slot_mapping
assert isinstance(slot_mapping, dict), (
f"Expected slot_mapping to be a dict, got {type(slot_mapping)}. "
)
layer_slot_mapping = slot_mapping.get(layer_name)
if layer_slot_mapping is not None:
assert hasattr(attn_layer.impl, "do_kv_cache_update"), (
f"{attn_layer.impl.__class__.__name__} does not support kv cache update"
)
attn_layer.impl.do_kv_cache_update(
attn_layer,
key,
value,
kv_cache,
layer_slot_mapping,
)
return torch.empty(0, device=kv_cache.device, dtype=kv_cache.dtype)
def unified_kv_cache_update_fake(
key: torch.Tensor,
value: torch.Tensor,
layer_name: str,
) -> torch.Tensor:
return torch.empty(0, device=key.device, dtype=key.dtype)
direct_register_custom_op(
op_name="unified_kv_cache_update",
op_func=unified_kv_cache_update,
fake_impl=unified_kv_cache_update_fake,
mutates_args=[],
)
@maybe_transfer_kv_layer
def unified_attention_with_output(
query: torch.Tensor,
key: torch.Tensor,
value: torch.Tensor,
output: torch.Tensor,
layer_name: str,
output_scale: torch.Tensor | None = None,
output_block_scale: torch.Tensor | None = None,
kv_cache_dummy_dep: torch.Tensor | None = None,
) -> None:
# kv_cache_dummy_dep is not used but accepting it creates a data dependency
# that ensures torch.compile preserves ordering between KV cache update and
# attention forward.
del kv_cache_dummy_dep
attn_metadata, self, kv_cache = get_attention_context(layer_name)
self.impl.forward(
self,
query,
key,
value,
kv_cache,
attn_metadata,
output=output,
output_scale=output_scale,
output_block_scale=output_block_scale,
)
def unified_attention_with_output_fake(
query: torch.Tensor,
key: torch.Tensor,
value: torch.Tensor,
output: torch.Tensor,
layer_name: str,
output_scale: torch.Tensor | None = None,
output_block_scale: torch.Tensor | None = None,
kv_cache_dummy_dep: torch.Tensor | None = None,
) -> None:
return
direct_register_custom_op(
op_name="unified_attention_with_output",
op_func=unified_attention_with_output,
mutates_args=["output", "output_block_scale"],
fake_impl=unified_attention_with_output_fake,
)

View File

@@ -4,9 +4,9 @@ import functools
import torch
from vllm.attention.layer import Attention
from vllm.config import CacheConfig
from vllm.config.vllm import VllmConfig
from vllm.model_executor.layers.attention import Attention
from vllm.model_executor.layers.quantization import QuantizationConfig
from vllm.v1.attention.backend import (
AttentionBackend,

View File

@@ -6,9 +6,9 @@ from copy import copy
import numpy as np
import torch
from vllm.attention.layer import Attention
from vllm.config import CacheConfig, VllmConfig
from vllm.logger import init_logger
from vllm.model_executor.layers.attention import Attention
from vllm.utils.math_utils import cdiv
from vllm.v1.attention.backend import (
AttentionBackend,

View File

@@ -5,9 +5,9 @@ from copy import copy
import torch
from vllm.attention.layer import Attention
from vllm.config import CacheConfig
from vllm.config.vllm import VllmConfig
from vllm.model_executor.layers.attention import Attention
from vllm.v1.attention.backend import (
AttentionBackend,
AttentionMetadata,

View File

@@ -0,0 +1,60 @@
# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
import inspect
from collections.abc import Callable
from functools import wraps
from vllm.distributed.kv_transfer import (
get_kv_transfer_group,
has_kv_transfer_group,
is_v1_kv_transfer_group,
)
def maybe_transfer_kv_layer(func: Callable) -> Callable:
"""Decorator that handles KV layer transfer prior and after execution of
an attention layer, if enabled. Otherwise, the wrapper is a no-op.
On entry: waits for the KV layer from the connector.
On exit: saves the KV layer to the connector.
"""
# Import at runtime to avoid circular dependency
from vllm.model_executor.layers.attention.attention import get_attention_context
# Inspect the signature ONCE when the decorator is applied.
sig = inspect.signature(func)
param_names = list(sig.parameters.keys())
# Find the index of 'layer_name' parameter.
try:
layer_name_index = param_names.index("layer_name")
except ValueError as e:
raise TypeError(
f"Function {func.__name__} must have a 'layer_name' parameter"
) from e
@wraps(func)
def wrapper(*args, **kwargs):
if not has_kv_transfer_group() or not is_v1_kv_transfer_group():
return func(*args, **kwargs)
layer_name: str = args[layer_name_index]
# Extract attention context (layer-specific metadata, layer, and kv_cache)
attn_metadata, attn_layer, kv_cache = get_attention_context(layer_name)
connector = get_kv_transfer_group()
if attn_metadata is None or not connector.has_connector_metadata():
return func(*args, **kwargs)
# Wait for KV layer on entry
connector.wait_for_layer_load(layer_name)
# Execute the function
result = func(*args, **kwargs)
# Save KV cache layer on exit
connector.save_kv_layer(layer_name, kv_cache, attn_metadata)
return result
return wrapper

371
vllm/model_executor/layers/attention/mla_attention.py Executable file → Normal file
View File

@@ -191,24 +191,38 @@ import functools
from abc import abstractmethod
from dataclasses import dataclass, field
from enum import Enum
from typing import ClassVar, Generic, TypeVar
from typing import TYPE_CHECKING, ClassVar, Generic, TypeVar, cast
if TYPE_CHECKING:
from flashinfer import BatchPrefillWithRaggedKVCacheWrapper
import torch
import torch.nn as nn
from tqdm import tqdm
import vllm.envs as envs
from vllm import _custom_ops as ops
from vllm import envs
from vllm._aiter_ops import rocm_aiter_ops
from vllm.config import ModelConfig, VllmConfig, get_current_vllm_config
from vllm.config import CacheConfig, ModelConfig, VllmConfig, get_current_vllm_config
from vllm.distributed.parallel_state import get_dcp_group, is_global_first_rank
from vllm.forward_context import ForwardContext, get_forward_context
from vllm.logger import init_logger
from vllm.model_executor.custom_op import CustomOp
from vllm.model_executor.layers.batch_invariant import (
vllm_is_batch_invariant,
from vllm.model_executor.layers.attention.attention import (
_init_kv_cache_quant,
get_attention_context,
set_default_quant_scales,
should_load_quant_weights,
)
from vllm.model_executor.layers.attention.kv_transfer_utils import (
maybe_transfer_kv_layer,
)
from vllm.model_executor.layers.attention_layer_base import AttentionLayerBase
from vllm.model_executor.layers.batch_invariant import vllm_is_batch_invariant
from vllm.model_executor.layers.linear import (
ColumnParallelLinear,
)
from vllm.model_executor.layers.quantization import QuantizationConfig
from vllm.model_executor.layers.quantization.input_quant_fp8 import QuantFP8
from vllm.model_executor.layers.quantization.utils.quant_utils import (
GroupShape,
@@ -217,11 +231,16 @@ from vllm.model_executor.layers.quantization.utils.quant_utils import (
from vllm.platforms import current_platform
from vllm.utils.flashinfer import has_nvidia_artifactory
from vllm.utils.math_utils import cdiv, round_down
from vllm.utils.torch_utils import (
direct_register_custom_op,
kv_cache_dtype_str_to_dtype,
)
from vllm.v1.attention.backend import (
AttentionBackend,
AttentionLayer,
AttentionMetadata,
AttentionMetadataBuilder,
AttentionType,
CommonAttentionMetadata,
MLAAttentionImpl,
)
@@ -234,7 +253,320 @@ from vllm.v1.attention.backends.utils import (
)
from vllm.v1.attention.ops.common import cp_lse_ag_out_rs
from vllm.v1.attention.ops.merge_attn_states import merge_attn_states
from vllm.v1.kv_cache_interface import AttentionSpec
from vllm.v1.attention.selector import get_attn_backend
from vllm.v1.kv_cache_interface import (
AttentionSpec,
KVCacheSpec,
MLAAttentionSpec,
)
logger = init_logger(__name__)
class MLAAttention(nn.Module, AttentionLayerBase):
"""Multi-Head Latent Attention layer.
This class takes query, and compressed key/value tensors as input.
The class does the following:
1. Store the input key and value tensors in the KV cache.
2. Perform (multi-head/multi-query/grouped-query) attention.
3. Return the output tensor.
"""
def __init__(
self,
num_heads: int,
scale: float,
qk_nope_head_dim: int,
qk_rope_head_dim: int,
v_head_dim: int,
q_lora_rank: int | None,
kv_lora_rank: int,
kv_b_proj: ColumnParallelLinear,
cache_config: CacheConfig | None = None,
quant_config: QuantizationConfig | None = None,
prefix: str = "",
use_sparse: bool = False,
indexer: object | None = None,
**extra_impl_args,
):
super().__init__()
self.num_heads = num_heads
self.scale = scale
self.qk_nope_head_dim = qk_nope_head_dim
self.qk_rope_head_dim = qk_rope_head_dim
self.v_head_dim = v_head_dim
self.q_lora_rank = q_lora_rank
self.kv_lora_rank = kv_lora_rank
self.head_size = kv_lora_rank + qk_rope_head_dim
self.layer_name = prefix
if cache_config is not None:
kv_cache_dtype = cache_config.cache_dtype
block_size = cache_config.block_size
calculate_kv_scales = cache_config.calculate_kv_scales
else:
kv_cache_dtype = "auto"
block_size = 16
calculate_kv_scales = False
self.quant_config = quant_config
# Initialize KV cache quantization attributes
self.kv_cache_dtype = kv_cache_dtype
self.calculate_kv_scales = calculate_kv_scales
_init_kv_cache_quant(self, quant_config, prefix)
dtype = torch.get_default_dtype()
self.attn_backend = get_attn_backend(
self.head_size,
dtype,
kv_cache_dtype,
block_size,
use_mla=True,
use_sparse=use_sparse,
)
if (
cache_config is not None
and cache_config.enable_prefix_caching
and vllm_is_batch_invariant()
and (
self.attn_backend.get_name() == "TRITON_MLA"
or self.attn_backend.get_name() == "FLASHINFER"
)
):
logger.warning_once(
"Disabling prefix caching for TRITON_MLA / FLASHINFER "
"with batch invariance, as it is not yet supported.",
scope="local",
)
cache_config.enable_prefix_caching = False
impl_cls = cast(type[MLAAttentionImpl], self.attn_backend.get_impl_cls())
self.impl = impl_cls(
num_heads=self.num_heads,
head_size=self.head_size,
scale=self.scale,
num_kv_heads=1,
alibi_slopes=None,
sliding_window=None,
kv_cache_dtype=self.kv_cache_dtype,
logits_soft_cap=None,
attn_type=AttentionType.DECODER,
kv_sharing_target_layer_name=None,
# MLA Args
q_lora_rank=self.q_lora_rank,
kv_lora_rank=self.kv_lora_rank,
qk_nope_head_dim=self.qk_nope_head_dim,
qk_rope_head_dim=self.qk_rope_head_dim,
qk_head_dim=self.qk_nope_head_dim + self.qk_rope_head_dim,
v_head_dim=self.v_head_dim,
kv_b_proj=kv_b_proj,
indexer=indexer,
**extra_impl_args,
)
self.use_direct_call = not current_platform.opaque_attention_op()
compilation_config = get_current_vllm_config().compilation_config
if prefix in compilation_config.static_forward_context:
raise ValueError(f"Duplicate layer name: {prefix}")
compilation_config.static_forward_context[prefix] = self
self.kv_cache = [
torch.tensor([])
for _ in range(
get_current_vllm_config().parallel_config.pipeline_parallel_size
)
]
self.use_sparse = use_sparse
# Initialize q/k/v range constants.
self.q_range = torch.tensor(envs.Q_SCALE_CONSTANT, dtype=torch.float32)
self.k_range = torch.tensor(envs.K_SCALE_CONSTANT, dtype=torch.float32)
self.v_range = torch.tensor(envs.V_SCALE_CONSTANT, dtype=torch.float32)
def forward(
self,
q: torch.Tensor,
kv_c_normed: torch.Tensor,
k_pe: torch.Tensor,
output_shape: torch.Size | None = None,
) -> torch.Tensor:
if self.calculate_kv_scales:
torch.ops.vllm.maybe_calc_kv_scales(q, kv_c_normed, k_pe, self.layer_name)
if self.use_direct_call:
forward_context: ForwardContext = get_forward_context()
attn_metadata = forward_context.attn_metadata
if isinstance(attn_metadata, dict):
attn_metadata = attn_metadata[self.layer_name]
self_kv_cache = self.kv_cache[forward_context.virtual_engine]
if self.attn_backend.accept_output_buffer:
output = torch.empty(output_shape, dtype=q.dtype, device=q.device)
self.impl.forward(
self,
q,
kv_c_normed,
k_pe,
self_kv_cache,
attn_metadata,
output=output,
)
return output
else:
return self.impl.forward(
self, q, kv_c_normed, k_pe, self_kv_cache, attn_metadata
)
else:
if self.attn_backend.accept_output_buffer:
output = torch.empty(output_shape, dtype=q.dtype, device=q.device)
torch.ops.vllm.unified_mla_attention_with_output(
q,
kv_c_normed,
k_pe,
output,
self.layer_name,
)
return output
else:
return torch.ops.vllm.unified_mla_attention(
q,
kv_c_normed,
k_pe,
self.layer_name,
)
def process_weights_after_loading(self, act_dtype: torch.dtype):
if hasattr(self.impl, "process_weights_after_loading"):
self.impl.process_weights_after_loading(act_dtype)
# If we should not load quant weights, we initialize the scales to 1.0
# as the default value. See [Note: Register q/k/v/prob scales in state dict]
# for more details.
quant_method = (
self.quant_config.get_quant_method(self, prefix=self.layer_name)
if self.quant_config
else None
)
if not should_load_quant_weights(quant_method):
set_default_quant_scales(self, register_buffer=False)
def calc_kv_scales(
self, q: torch.Tensor, kv_c_normed: torch.Tensor, k_pe: torch.Tensor
) -> None:
"""Optional scale calculation for MLA inputs.
Mirrors Attention.calc_kv_scales. Not all MLA backends require this
"""
# Use safe defaults if ranges are not present
q_range = getattr(self, "q_range", torch.tensor(1.0))
k_range = getattr(self, "k_range", torch.tensor(1.0))
v_range = getattr(self, "v_range", torch.tensor(1.0))
self._q_scale.copy_(torch.abs(q).max() / q_range)
# kv_c_normed is the compressed KV representation; use it for k/v
kv_abs_max = torch.abs(kv_c_normed).max()
self._k_scale.copy_(kv_abs_max / k_range)
self._v_scale.copy_(kv_abs_max / v_range)
self._q_scale_float = self._q_scale.item()
self._k_scale_float = self._k_scale.item()
self._v_scale_float = self._v_scale.item()
self.calculate_kv_scales = False
def get_attn_backend(self) -> type[AttentionBackend]:
return self.attn_backend
def get_kv_cache_spec(self, vllm_config: VllmConfig) -> KVCacheSpec:
kv_cache_dtype = kv_cache_dtype_str_to_dtype(
self.kv_cache_dtype, vllm_config.model_config
)
return MLAAttentionSpec(
block_size=vllm_config.cache_config.block_size,
num_kv_heads=1,
head_size=self.head_size,
dtype=kv_cache_dtype,
cache_dtype_str=vllm_config.cache_config.cache_dtype,
)
@maybe_transfer_kv_layer
def unified_mla_attention(
q: torch.Tensor,
kv_c_normed: torch.Tensor,
k_pe: torch.Tensor,
layer_name: str,
) -> torch.Tensor:
attn_metadata, self, kv_cache = get_attention_context(layer_name)
output = self.impl.forward(self, q, kv_c_normed, k_pe, kv_cache, attn_metadata)
return output
def unified_mla_attention_fake(
q: torch.Tensor,
kv_c_normed: torch.Tensor,
k_pe: torch.Tensor,
layer_name: str,
) -> torch.Tensor:
return torch.empty_like(q).contiguous()
direct_register_custom_op(
op_name="unified_mla_attention",
op_func=unified_mla_attention,
mutates_args=[],
fake_impl=unified_mla_attention_fake,
dispatch_key=current_platform.dispatch_key,
)
@maybe_transfer_kv_layer
def unified_mla_attention_with_output(
q: torch.Tensor,
kv_c_normed: torch.Tensor,
k_pe: torch.Tensor,
output: torch.Tensor,
layer_name: str,
output_scale: torch.Tensor | None = None,
output_block_scale: torch.Tensor | None = None,
) -> None:
attn_metadata, self, kv_cache = get_attention_context(layer_name)
self.impl.forward(
self,
q,
kv_c_normed,
k_pe,
kv_cache,
attn_metadata,
output=output,
output_scale=output_scale,
output_block_scale=output_block_scale,
)
def unified_mla_attention_with_output_fake(
q: torch.Tensor,
kv_c_normed: torch.Tensor,
k_pe: torch.Tensor,
output: torch.Tensor,
layer_name: str,
output_scale: torch.Tensor | None = None,
output_block_scale: torch.Tensor | None = None,
) -> None:
return
direct_register_custom_op(
op_name="unified_mla_attention_with_output",
op_func=unified_mla_attention_with_output,
mutates_args=["output", "output_block_scale"],
fake_impl=unified_mla_attention_with_output_fake,
dispatch_key=current_platform.dispatch_key,
)
class QueryLenSupport(Enum):
@@ -266,15 +598,12 @@ except ImportError:
from flash_attn import flash_attn_varlen_func # type: ignore[no-redef]
is_vllm_fa = False
try:
from flashinfer import BatchPrefillWithRaggedKVCacheWrapper
from flashinfer.prefill import cudnn_batch_prefill_with_kv_cache # noqa: F401
flashinfer_available = True
except ImportError:
BatchPrefillWithRaggedKVCacheWrapper = object
@functools.cache
def flashinfer_available() -> bool:
import importlib.util
flashinfer_available = False
return importlib.util.find_spec("flashinfer") is not None
def dynamic_per_batched_tensor_quant(
@@ -398,8 +727,8 @@ class MLACommonPrefillMetadata:
@dataclass
class FlashInferPrefillMetadata(MLACommonPrefillMetadata):
prefill_main: BatchPrefillWithRaggedKVCacheWrapper | None = None
prefill_chunks: list[BatchPrefillWithRaggedKVCacheWrapper] = field(
prefill_main: "BatchPrefillWithRaggedKVCacheWrapper | None" = None
prefill_chunks: "list[BatchPrefillWithRaggedKVCacheWrapper]" = field(
default_factory=list
)
@@ -495,7 +824,7 @@ def use_flashinfer_prefill() -> bool:
vllm_config = get_current_vllm_config()
if not (
not vllm_config.attention_config.disable_flashinfer_prefill
and flashinfer_available
and flashinfer_available()
and not vllm_config.attention_config.use_cudnn_prefill
and current_platform.is_device_capability_family(100)
):
@@ -509,7 +838,7 @@ def use_cudnn_prefill() -> bool:
vllm_config = get_current_vllm_config()
return (
flashinfer_available
flashinfer_available()
and vllm_config.attention_config.use_cudnn_prefill
and current_platform.is_device_capability_family(100)
and has_nvidia_artifactory()
@@ -731,6 +1060,8 @@ class MLACommonMetadataBuilder(AttentionMetadataBuilder[M]):
has_context = True
if self._fi_prefill_main is None:
from flashinfer import BatchPrefillWithRaggedKVCacheWrapper
self._fi_prefill_main = BatchPrefillWithRaggedKVCacheWrapper(
self._workspace_buffer, "NHD", backend="cutlass"
)
@@ -739,6 +1070,8 @@ class MLACommonMetadataBuilder(AttentionMetadataBuilder[M]):
num_chunks = chunked_context.cu_seq_lens.shape[0]
# Allocate more prefill chunk wrappers if needed
if len(self._fi_prefill_chunks) < num_chunks:
from flashinfer import BatchPrefillWithRaggedKVCacheWrapper
for _ in range(len(self._fi_prefill_chunks), num_chunks):
self._fi_prefill_chunks.append(
BatchPrefillWithRaggedKVCacheWrapper(
@@ -1513,6 +1846,8 @@ class MLACommonImpl(MLACommonBaseImpl[M], Generic[M]):
):
assert isinstance(prefill, CudnnPrefillMetadata)
assert prefill.query_seq_lens is not None
from flashinfer.prefill import cudnn_batch_prefill_with_kv_cache
output, lse = cudnn_batch_prefill_with_kv_cache(
q=q,
k_cache=k,
@@ -1572,6 +1907,8 @@ class MLACommonImpl(MLACommonBaseImpl[M], Generic[M]):
assert prefill.chunked_context is not None
assert prefill.chunked_context.seq_lens[chunk_idx] is not None
assert prefill.query_seq_lens is not None
from flashinfer.prefill import cudnn_batch_prefill_with_kv_cache
return cudnn_batch_prefill_with_kv_cache(
q=q,
k_cache=k,

View File

@@ -4,11 +4,11 @@ import functools
import torch
from vllm.attention.layer import Attention
from vllm.config import CacheConfig, VllmConfig
from vllm.forward_context import ForwardContext, get_forward_context
from vllm.logger import init_logger
from vllm.model_executor.custom_op import CustomOp
from vllm.model_executor.layers.attention import Attention
from vllm.utils.math_utils import cdiv
from vllm.utils.torch_utils import direct_register_custom_op
from vllm.v1.attention.backend import (

View File

@@ -4,9 +4,9 @@ from dataclasses import dataclass
import torch
from vllm.attention.layer import MLAAttention
from vllm.config import CacheConfig
from vllm.model_executor.custom_op import PluggableLayer
from vllm.model_executor.layers.attention import MLAAttention
from vllm.model_executor.layers.quantization import QuantizationConfig

View File

@@ -19,12 +19,12 @@ from compressed_tensors.quantization import (
from compressed_tensors.transform import TransformConfig
import vllm.envs as envs
from vllm.attention.layer import Attention
from vllm.distributed import (
get_tensor_model_parallel_rank,
get_tensor_model_parallel_world_size,
)
from vllm.logger import init_logger
from vllm.model_executor.layers.attention import Attention
from vllm.model_executor.layers.fused_moe import FusedMoE
from vllm.model_executor.layers.linear import (
LinearBase,

View File

@@ -11,9 +11,9 @@ import vllm.envs as envs
import vllm.model_executor.layers.fused_moe.modular_kernel as mk
from vllm import _custom_ops as ops
from vllm._aiter_ops import rocm_aiter_ops
from vllm.attention.layer import Attention
from vllm.distributed import get_tensor_model_parallel_world_size
from vllm.logger import init_logger
from vllm.model_executor.layers.attention import Attention
from vllm.model_executor.layers.batch_invariant import (
vllm_is_batch_invariant,
)

View File

@@ -11,8 +11,8 @@ from torch.nn.parameter import Parameter
import vllm.envs as envs
import vllm.model_executor.layers.fused_moe.modular_kernel as mk
from vllm._custom_ops import cutlass_scaled_fp4_mm, scaled_fp4_quant
from vllm.attention.layer import Attention
from vllm.logger import init_logger
from vllm.model_executor.layers.attention import Attention
from vllm.model_executor.layers.fused_moe.config import (
FusedMoEConfig,
FusedMoEQuantConfig,

View File

@@ -7,9 +7,9 @@ import torch
from torch.nn.parameter import Parameter
from vllm import envs
from vllm.attention.layer import Attention
from vllm.config import get_current_vllm_config
from vllm.logger import init_logger
from vllm.model_executor.layers.attention import Attention
from vllm.model_executor.layers.fused_moe import (
FusedMoE,
FusedMoEConfig,

View File

@@ -8,8 +8,8 @@ import regex as re
import torch
from torch.nn.parameter import Parameter
from vllm.attention.layer import Attention
from vllm.logger import init_logger
from vllm.model_executor.layers.attention import Attention
from vllm.model_executor.layers.linear import (
LinearBase,
LinearMethodBase,

View File

@@ -7,8 +7,8 @@ import torch
from torch.nn.parameter import Parameter
from vllm import _custom_ops as ops
from vllm.attention.layer import Attention
from vllm.logger import init_logger
from vllm.model_executor.layers.attention import Attention
from vllm.model_executor.layers.linear import LinearBase, UnquantizedLinearMethod
from vllm.model_executor.layers.quantization import QuantizationMethods
from vllm.model_executor.layers.quantization.base_config import QuantizeMethodBase

View File

@@ -6,8 +6,8 @@ from typing import TYPE_CHECKING, Any, Optional, cast
import torch
from vllm.attention.layer import Attention
from vllm.logger import init_logger
from vllm.model_executor.layers.attention import Attention
from vllm.model_executor.layers.fused_moe import FusedMoE
from vllm.model_executor.layers.linear import (
LinearBase,