[Spec Decode] Support hybrid attention models in extract_hidden_states (#39949)

Signed-off-by: mgoin <[email protected]>
Co-authored-by: Claude Opus 4.6 (1M context) <[email protected]>
This commit is contained in:
Michael Goin
2026-05-13 10:45:53 -07:00
committed by GitHub
co-authored by Claude Opus 4.6
parent 5794c65f8c
commit 2f821faeae
14 changed files with 225 additions and 115 deletions
+13
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@@ -129,6 +129,19 @@ steps:
- pytest -v -s -m 'cpu_test' v1/kv_connector/unit
- pytest -v -s -m 'cpu_test' v1/metrics
- label: Extract Hidden States Integration
key: extract-hidden-states-integration
timeout_in_minutes: 20
device: h200_18gb
source_file_dependencies:
- vllm/v1/spec_decode/extract_hidden_states.py
- vllm/model_executor/models/extract_hidden_states.py
- vllm/transformers_utils/configs/extract_hidden_states.py
- tests/v1/kv_connector/extract_hidden_states_integration
commands:
- export VLLM_WORKER_MULTIPROC_METHOD=spawn
- pytest -v -s v1/kv_connector/extract_hidden_states_integration
- label: Regression
key: regression
timeout_in_minutes: 20
@@ -83,7 +83,7 @@ def register_predictable_model():
def test_extract_hidden_states_with_predictable_dummy_model(
predictable_llama_config_path, tmp_path
predictable_llama_config_path, tmp_path, monkeypatch
):
"""Comprehensive test using a predictable dummy model with synthetic weights.
@@ -94,6 +94,12 @@ def test_extract_hidden_states_with_predictable_dummy_model(
3. Layer ordering is preserved correctly (non-sequential layer IDs)
4. Multiple prompts of different lengths produce consistent layer values
"""
# Force fork so the engine worker inherits the autouse fixture's
# ModelRegistry.register_model("PredictableLlamaForCausalLM", ...).
# Spawn (the CI default) starts a fresh Python process that wouldn't
# see the registration.
monkeypatch.setenv("VLLM_WORKER_MULTIPROC_METHOD", "fork")
# Test with non-sequential layer ordering to verify correct association
layer_ids = [5, 2, 10]
num_layers = len(layer_ids)
@@ -153,3 +159,55 @@ def test_extract_hidden_states_with_predictable_dummy_model(
f"but got mean={layer_hidden.mean():.3f}, "
f"min={layer_hidden.min():.3f}, max={layer_hidden.max():.3f}"
)
def test_extract_hidden_states_qwen35_hybrid_smoke(tmp_path):
"""Smoke test for Qwen3.5 hybrid (mamba + full-attention) models.
Uses load_format="dummy" to just check shape/plumbing.
"""
layer_ids = [5, 11, 17]
hidden_size = 1024 # Qwen/Qwen3.5-0.8B hidden_size
llm = LLM(
model="Qwen/Qwen3.5-0.8B",
speculative_config={
"method": "extract_hidden_states",
"num_speculative_tokens": 1,
"draft_model_config": {
"hf_config": {"eagle_aux_hidden_state_layer_ids": layer_ids}
},
},
kv_transfer_config={
"kv_connector": "ExampleHiddenStatesConnector",
"kv_role": "kv_producer",
"kv_connector_extra_config": {"shared_storage_path": str(tmp_path)},
},
max_model_len=256,
enforce_eager=True,
gpu_memory_utilization=0.4,
load_format="dummy",
)
prompts = ["Hello world", "Test prompt with several tokens"]
sampling_params = SamplingParams(max_tokens=1, temperature=0.0)
outputs = llm.generate(prompts, sampling_params)
del llm
gc.collect()
assert len(outputs) == len(prompts)
for output in outputs:
assert output.kv_transfer_params is not None
hidden_states_path = output.kv_transfer_params.get("hidden_states_path")
assert hidden_states_path is not None
assert os.path.exists(hidden_states_path)
with safe_open(hidden_states_path, "pt") as f:
token_ids = f.get_tensor("token_ids")
hidden_states = f.get_tensor("hidden_states")
assert torch.equal(token_ids, torch.tensor(output.prompt_token_ids))
assert hidden_states.shape == (
len(output.prompt_token_ids),
len(layer_ids),
hidden_size,
)
@@ -11,7 +11,6 @@ import pytest
import torch
from vllm import SamplingParams
from vllm.config import KVTransferConfig
from vllm.distributed.kv_transfer.kv_connector.v1 import KVConnectorRole
# ruff: noqa: E501
@@ -44,11 +43,9 @@ class DecodeBenchTestRunner:
# Create vllm config with DecodeBenchConnector
vllm_config = create_vllm_config(
block_size=block_size, max_num_batched_tokens=1000
)
vllm_config.kv_transfer_config = KVTransferConfig(
block_size=block_size,
max_num_batched_tokens=1000,
kv_connector="DecodeBenchConnector",
kv_role="kv_both",
)
self.vllm_config = vllm_config
@@ -35,10 +35,11 @@ def _make_empty_scheduler_output():
def test_kv_connector_mixin_clears_metadata():
vllm_config = create_vllm_config()
vllm_config.kv_transfer_config.kv_connector = "TestExampleConnector"
vllm_config.kv_transfer_config.kv_role = "kv_both"
vllm_config.kv_transfer_config.kv_connector_extra_config["name"] = "unit"
vllm_config = create_vllm_config(
kv_connector="TestExampleConnector",
kv_role="kv_both",
kv_connector_extra_config={"name": "unit"},
)
kv_cache_config = KVCacheConfig(
num_blocks=0, kv_cache_tensors=[], kv_cache_groups=[]
@@ -130,17 +130,14 @@ KVConnectorFactory.register_connector(
@pytest.fixture
def mc() -> MultiConnector:
"""MultiConnector using two mocked connectors"""
vllm_config = create_vllm_config()
mock_connector_config = {
"kv_connector": "MockConnector",
"kv_role": "kv_both",
"kv_connector_module_path": "tests.v1.kv_connector.unit.test_multi_connector",
}
vllm_config.kv_transfer_config = KVTransferConfig(
vllm_config = create_vllm_config(
kv_connector="MultiConnector",
kv_role="kv_both",
kv_connector_extra_config={
"connectors": [mock_connector_config, mock_connector_config],
},
@@ -405,39 +402,35 @@ def test_multi_connector_handle_preemptions_integration():
try:
# Configure MultiConnector with two TestExampleConnectors
kv_transfer_config = KVTransferConfig(
kv_connector="MultiConnector",
kv_role="kv_both",
kv_connector_extra_config={
"connectors": [
{
"kv_connector": "TestExampleConnector",
"kv_role": "kv_both",
"kv_connector_extra_config": {
"shared_storage_path": str(storage_path / "s1"),
"name": "preempt1",
},
"kv_connector_module_path": "tests.v1.kv_connector.unit.utils",
connectors_extra_config = {
"connectors": [
{
"kv_connector": "TestExampleConnector",
"kv_role": "kv_both",
"kv_connector_extra_config": {
"shared_storage_path": str(storage_path / "s1"),
"name": "preempt1",
},
{
"kv_connector": "TestExampleConnector",
"kv_role": "kv_both",
"kv_connector_extra_config": {
"shared_storage_path": str(storage_path / "s2"),
"name": "preempt2",
},
"kv_connector_module_path": "tests.v1.kv_connector.unit.utils",
"kv_connector_module_path": "tests.v1.kv_connector.unit.utils",
},
{
"kv_connector": "TestExampleConnector",
"kv_role": "kv_both",
"kv_connector_extra_config": {
"shared_storage_path": str(storage_path / "s2"),
"name": "preempt2",
},
]
},
)
"kv_connector_module_path": "tests.v1.kv_connector.unit.utils",
},
]
}
vllm_config = create_vllm_config(
block_size=16,
max_num_batched_tokens=100,
kv_connector_extra_config=kv_transfer_config.kv_connector_extra_config,
kv_connector="MultiConnector",
kv_connector_extra_config=connectors_extra_config,
)
vllm_config.kv_transfer_config = kv_transfer_config
# Create scheduler - this initializes the MultiConnector with SCHEDULER role
scheduler = create_scheduler(vllm_config, num_blocks=10)
@@ -973,7 +966,6 @@ def test_multi_connector_worker_metadata(mc):
def _make_multi_connector(connector_names: list[str]) -> MultiConnector:
"""Build a MultiConnector wrapping the given registered connectors."""
vllm_config = create_vllm_config()
connectors = [
{
"kv_connector": name,
@@ -982,9 +974,8 @@ def _make_multi_connector(connector_names: list[str]) -> MultiConnector:
}
for name in connector_names
]
vllm_config.kv_transfer_config = KVTransferConfig(
vllm_config = create_vllm_config(
kv_connector="MultiConnector",
kv_role="kv_both",
kv_connector_extra_config={"connectors": connectors},
)
kv_cache_config = KVCacheConfig(
+2
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@@ -102,6 +102,7 @@ def create_vllm_config(
attention_backend: str | None = None,
kv_load_failure_policy: Literal["recompute", "fail"] = "fail",
kv_connector: str = "NixlConnector",
kv_connector_module_path: str | None = None,
kv_role: str = "kv_both",
disable_hybrid_kv_cache_manager: bool | None = None,
) -> VllmConfig:
@@ -130,6 +131,7 @@ def create_vllm_config(
)
kv_transfer_config = KVTransferConfig(
kv_connector=kv_connector,
kv_connector_module_path=kv_connector_module_path,
kv_role=kv_role,
enable_permute_local_kv=enable_permute_local_kv,
kv_connector_extra_config=kv_connector_extra_config or {},
+39 -14
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@@ -1316,6 +1316,10 @@ class VllmConfig:
"the `reasoning_start_str` and `reasoning_end_str`."
)
# Resolve kv_offloading-derived connector name into kv_transfer_config
# before the HMA check below, which inspects the connector class.
self._post_init_kv_transfer_config()
# Hybrid KV cache manager (HMA) runtime rules:
# - Explicit enable (--no-disable-kv-cache-manager): error if runtime
# disables it
@@ -1353,18 +1357,42 @@ class VllmConfig:
if self.scheduler_config.disable_hybrid_kv_cache_manager is None:
# Default to disable HMA, but only if the user didn't express a preference.
if self.kv_transfer_config is not None:
# NOTE(Kuntai): turn HMA off for connector unless specifically enabled.
need_disable_hybrid_kv_cache_manager = True
logger.warning(
"Turning off hybrid kv cache manager because "
"`--kv-transfer-config` is set. This will reduce the "
"performance of vLLM on LLMs with sliding window attention "
"or Mamba attention. If you are a developer of kv connector"
", please consider supporting hybrid kv cache manager for "
"your connector by making sure your connector is a subclass"
" of `SupportsHMA` defined in kv_connector/v1/base.py and"
" use --no-disable-hybrid-kv-cache-manager to start vLLM."
from vllm.config.kv_transfer import KVTransferConfig
from vllm.distributed.kv_transfer.kv_connector.factory import (
KVConnectorFactory,
)
from vllm.distributed.kv_transfer.kv_connector.v1.base import (
supports_hma,
)
connector_cls = KVConnectorFactory.get_connector_class(
self.kv_transfer_config
)
all_support_hma = supports_hma(connector_cls)
# MultiConnector subclasses SupportsHMA; only effectively
# supports HMA when every sub-connector does.
if all_support_hma and connector_cls.__name__ == "MultiConnector":
sub_ktcs = self.kv_transfer_config.kv_connector_extra_config.get(
"connectors", []
)
all_support_hma = all(
supports_hma(
KVConnectorFactory.get_connector_class(
KVTransferConfig(**sub)
)
)
for sub in sub_ktcs
)
if not all_support_hma:
need_disable_hybrid_kv_cache_manager = True
logger.warning(
"Turning off hybrid kv cache manager because "
"connector %s does not subclass `SupportsHMA`. "
"This will reduce performance on models with "
"sliding window or Mamba attention. See "
"kv_connector/v1/base.py for details.",
connector_cls.__name__,
)
self.scheduler_config.disable_hybrid_kv_cache_manager = (
need_disable_hybrid_kv_cache_manager
)
@@ -1406,10 +1434,7 @@ class VllmConfig:
if "-quant_fp8" not in custom_ops:
custom_ops.append("+quant_fp8")
# Handle the KV connector configs
self._post_init_kv_transfer_config()
self._verify_kv_transfer_compat()
# Log the custom passes that are enabled
self.compilation_config.pass_config.log_enabled_passes()
@@ -12,6 +12,7 @@ from vllm.distributed.kv_transfer.kv_connector.v1.base import (
KVConnectorBase_V1,
KVConnectorMetadata,
KVConnectorRole,
SupportsHMA,
)
from vllm.logger import init_logger
from vllm.v1.attention.backend import AttentionMetadata
@@ -30,13 +31,9 @@ def extract_from_kv_cache(
slot_mapping: torch.Tensor,
num_tokens: int,
) -> torch.Tensor:
"""Extract data from KV cache
Assume the shape of the kv_cache is (num_pages, page_size, num_heads, head_size)
"""
padded_kv = kv_cache.flatten(0, 1)[slot_mapping]
# shape: [len(slot_mapping), num_heads, head_size]
return padded_kv[:num_tokens] # shape: [num_tokens, num_heads, head_size]
"""Extract data from KV cache."""
block_size = kv_cache.shape[1]
return kv_cache[slot_mapping // block_size, slot_mapping % block_size][:num_tokens]
@dataclass
@@ -47,8 +44,6 @@ class ReqMeta:
filename: str
# Request tokens
token_ids: torch.Tensor
# Slot mappings, should have the same length as token_ids
slot_mapping: torch.Tensor
# Whether this request is a new request or partially computed already
new_req: bool
@@ -57,24 +52,12 @@ class ReqMeta:
req_id: str,
filename: str,
token_ids: list[int],
block_ids: list[int],
block_size: int,
new_req: bool,
) -> "ReqMeta":
token_ids_tensor = torch.tensor(token_ids)
block_ids_tensor = torch.tensor(block_ids)
num_blocks = block_ids_tensor.shape[0]
block_offsets = torch.arange(0, block_size)
slot_mapping = (
block_offsets.reshape((1, block_size))
+ block_ids_tensor.reshape((num_blocks, 1)) * block_size
)
slot_mapping = slot_mapping.flatten()
return ReqMeta(
req_id=req_id,
filename=filename,
token_ids=token_ids_tensor,
slot_mapping=slot_mapping,
token_ids=torch.tensor(token_ids),
new_req=new_req,
)
@@ -88,18 +71,12 @@ class ExampleHiddenStatesConnectorMetadata(KVConnectorMetadata):
req_id: str,
filename: str,
token_ids: list[int],
block_ids: list[int],
block_size: int,
new_req: bool = True,
) -> None:
self.requests.append(
ReqMeta.make_meta(
req_id, filename, token_ids, block_ids, block_size, new_req
)
)
self.requests.append(ReqMeta.make_meta(req_id, filename, token_ids, new_req))
class ExampleHiddenStatesConnector(KVConnectorBase_V1):
class ExampleHiddenStatesConnector(KVConnectorBase_V1, SupportsHMA):
"""
Simple debug implementation of a HiddenStatesConnector.
@@ -206,9 +183,16 @@ class ExampleHiddenStatesConnector(KVConnectorBase_V1):
assert isinstance(connector_metadata, ExampleHiddenStatesConnectorMetadata)
os.makedirs(self._storage_path, exist_ok=True)
slot_mapping = attn_metadata.slot_mapping
offset = 0
for request in connector_metadata.requests:
num_tokens = request.token_ids.shape[0]
req_slot_mapping = slot_mapping[offset : offset + num_tokens]
offset += num_tokens
hidden_states = extract_from_kv_cache(
kv_layer, request.slot_mapping, request.token_ids.shape[0]
kv_layer, req_slot_mapping, num_tokens
)
tensors = {
"hidden_states": hidden_states.detach().cpu(),
@@ -269,8 +253,6 @@ class ExampleHiddenStatesConnector(KVConnectorBase_V1):
new_req.req_id,
filename=filename,
token_ids=token_ids,
block_ids=new_req.block_ids[0],
block_size=self._block_size,
)
self._request_filenames[new_req.req_id] = filename
self._active_requests[new_req.req_id] = new_req
@@ -298,8 +280,6 @@ class ExampleHiddenStatesConnector(KVConnectorBase_V1):
req_id=req_id,
filename=filename,
token_ids=cached_req.prompt_token_ids or [],
block_ids=req_block_ids,
block_size=self._block_size,
new_req=False,
)
@@ -331,6 +311,13 @@ class ExampleHiddenStatesConnector(KVConnectorBase_V1):
return False, {"hidden_states_path": req_filename}
def request_finished_all_groups(
self,
request: "Request",
block_ids: tuple[list[int], ...],
) -> tuple[bool, dict[str, Any] | None]:
return self.request_finished(request, block_ids[0])
@classmethod
def get_required_kvcache_layout(cls, vllm_config: "VllmConfig") -> str | None:
"""
@@ -34,8 +34,8 @@ from vllm.v1.attention.backend import (
)
from vllm.v1.kv_cache_interface import (
AttentionSpec,
HiddenStateCacheSpec,
KVCacheSpec,
MLAAttentionSpec,
)
########## Custom Ops ########
@@ -79,13 +79,12 @@ def dummy_attention(layer_name, _placeholder):
def basic_cache(
to_cache: torch.Tensor, # shape: [num_blocks, block_size, num_heads, head_size]
kv_cache: torch.Tensor, # shape: [seq_len, num_heads, head_size]
to_cache: torch.Tensor, # shape: [seq_len, num_heads, head_size]
kv_cache: torch.Tensor, # shape: [num_blocks, block_size, num_heads, head_size]
slot_mapping: torch.Tensor, # shape: [seq_len]
):
num_blocks, block_size, num_heads, head_size = kv_cache.shape
token_kv_cache = kv_cache.view(num_blocks * block_size, num_heads, head_size)
token_kv_cache[slot_mapping] = to_cache
block_size = kv_cache.shape[1]
kv_cache[slot_mapping // block_size, slot_mapping % block_size] = to_cache
######### CacheOnlyAttentionBackend ########
@@ -322,11 +321,9 @@ class CacheOnlyAttentionLayer(nn.Module, AttentionLayerBase):
return self.attn_backend
def get_kv_cache_spec(self, vllm_config: VllmConfig) -> KVCacheSpec:
# Note: we use MLAAttentionSpec here to because it will
# produce page sizes of (block_size * num_kv_heads * head_size * dtype_size)
# whereas FullAttentionSpec will add an additional factor of 2
return MLAAttentionSpec(
block_size=self.block_size,
# Re-read block_size: hybrid models may bump it after __init__.
return HiddenStateCacheSpec(
block_size=vllm_config.cache_config.block_size,
num_kv_heads=self.num_heads,
head_size=self.head_size,
dtype=self.kv_cache_torch_dtype,
+26 -6
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@@ -18,9 +18,11 @@ from vllm.logger import init_logger
from vllm.utils.hashing import sha256_cbor, xxhash_cbor
from vllm.utils.math_utils import cdiv, round_up
from vllm.utils.mem_utils import format_gib
from vllm.utils.torch_utils import get_dtype_size
from vllm.v1.kv_cache_interface import (
ChunkedLocalAttentionSpec,
FullAttentionSpec,
HiddenStateCacheSpec,
KVCacheConfig,
KVCacheGroupSpec,
KVCacheSpec,
@@ -1650,15 +1652,33 @@ def get_kv_cache_groups(
_annotate_eagle_groups_deepseek_v4(vllm_config, kv_cache_spec, kv_cache_groups)
return kv_cache_groups
# Pull HiddenStateCacheSpec layers out before the general multi-group
# path so they don't affect page-size unification or grouping.
hidden_specs = {
k: v for k, v in kv_cache_spec.items() if isinstance(v, HiddenStateCacheSpec)
}
filtered_spec = {
k: v
for k, v in kv_cache_spec.items()
if not isinstance(v, HiddenStateCacheSpec)
}
# As KVCacheManager can only allocate memory of one size, we need to unify
# the page size of the layers. For cases cannot be unified, this function
# will raise an error.
kv_cache_spec = unify_kv_cache_spec_page_size(kv_cache_spec)
# Model contains multiple attention types, but KV cache of all layers
# have the same physical memory per block per layer. Split the layers
# into groups with the same number of layers, and thus same total page
# size.
return _get_kv_cache_groups_uniform_page_size(kv_cache_spec)
filtered_spec = unify_kv_cache_spec_page_size(filtered_spec)
groups = _get_kv_cache_groups_uniform_page_size(filtered_spec)
# Add hidden-state layers back with page aligned to the common page.
if hidden_specs:
common_page = get_uniform_page_size([g.kv_cache_spec for g in groups])
for name, spec in hidden_specs.items():
per_token = spec.num_kv_heads * spec.head_size * get_dtype_size(spec.dtype)
new_bs = max(common_page // per_token, 1)
aligned = replace(spec, block_size=new_bs, page_size_padded=common_page)
groups.append(KVCacheGroupSpec([name], aligned))
return groups
def generate_scheduler_kv_cache_config(
@@ -16,6 +16,7 @@ from vllm.v1.kv_cache_interface import (
ChunkedLocalAttentionSpec,
CrossAttentionSpec,
FullAttentionSpec,
HiddenStateCacheSpec,
KVCacheSpec,
MambaSpec,
MLAAttentionSpec,
@@ -1143,6 +1144,7 @@ spec_manager_map: dict[type[KVCacheSpec], type[SingleTypeKVCacheManager]] = {
FullAttentionSpec: FullAttentionManager,
TQFullAttentionSpec: FullAttentionManager,
MLAAttentionSpec: FullAttentionManager,
HiddenStateCacheSpec: FullAttentionManager,
SlidingWindowSpec: SlidingWindowManager,
SlidingWindowMLASpec: SlidingWindowManager,
ChunkedLocalAttentionSpec: ChunkedLocalAttentionManager,
+7
View File
@@ -396,6 +396,13 @@ class MLAAttentionSpec(FullAttentionSpec):
)
@dataclass(frozen=True, kw_only=True)
class HiddenStateCacheSpec(MLAAttentionSpec):
"""Marker for hidden-state cache layers used by extract_hidden_states."""
pass
@dataclass(frozen=True, kw_only=True)
class ChunkedLocalAttentionSpec(AttentionSpec):
attention_chunk_size: int
+9 -5
View File
@@ -42,6 +42,7 @@ class ExtractHiddenStatesProposer:
self.model: nn.Module | None = None
self.attn_layer_names: list[str] = []
self.attn_metadata_builder: AttentionMetadataBuilder | None = None
self.kv_cache_gid: int = -1
# Maximum number of tokens for buffers
max_batch_size = vllm_config.scheduler_config.max_num_seqs
@@ -374,9 +375,12 @@ class ExtractHiddenStatesProposer:
)
def validate_same_kv_cache_group(self, kv_cache_config: KVCacheConfig) -> None:
"""Validate all drafting layers belong to the same KV cache group.
With exactly one attention layer (asserted in load_model), this is
trivially satisfied.
"""
"""Validate all drafting layers belong to the same KV cache group
and record the group index for common_attn_metadata selection."""
assert len(self.attn_layer_names) == 1
layer = self.attn_layer_names[0]
for gid, group in enumerate(kv_cache_config.kv_cache_groups):
if layer in group.layer_names:
self.kv_cache_gid = gid
return
raise ValueError(f"Cache-only layer {layer!r} not in any KV cache group")
+7 -1
View File
@@ -2347,7 +2347,13 @@ class GPUModelRunner(
if self.speculative_config and spec_decode_common_attn_metadata is None:
if isinstance(
self.drafter, (EagleProposer, DFlashProposer, Gemma4Proposer)
self.drafter,
(
EagleProposer,
DFlashProposer,
Gemma4Proposer,
ExtractHiddenStatesProposer,
),
):
if self.drafter.kv_cache_gid == kv_cache_gid:
spec_decode_common_attn_metadata = cm