A high-throughput and memory-efficient inference and serving engine for LLMs
Mirrored from https://github.com/tduncan-lum/Nvidia-Optimization-Stack---VLLM.git
Synced Nov 14, 23:45 UTC
[v1][attention] Support Hybrid Allocator + FlashInfer (#21412)
Signed-off-by: Chen Zhang <zhangch99@outlook.com>
Chen Zhang committed
Jul 29, 2025 at 18:45 UTC
555e7225bcb9cdf9b037ce064e48987dbc3e13a0
16 files changed
+85
-57
tests/v1/attention/test_attention_backends.py
+11
-8
@@ -198,7 +198,8 @@ class MockAttentionLayer:
198
199
200
def run_attention_backend(backend: _Backend, kv_cache_spec: FullAttentionSpec,
201
- vllm_config, device: torch.device,
201
+ layer_names: list[str], vllm_config,
202
+ device: torch.device,
203
common_attn_metadata: CommonAttentionMetadata,
204
query: torch.Tensor, key: torch.Tensor,
205
value: torch.Tensor,
@@ -211,31 +212,33 @@ def run_attention_backend(backend: _Backend, kv_cache_spec: FullAttentionSpec,
212
if backend == _Backend.FLASHINFER_VLLM_V1:
213
import unittest.mock
214
214
- from vllm.v1.attention.backends.flashinfer import PerLayerParameters
215
+ from vllm.v1.attention.backends.utils import PerLayerParameters
216
216
- def mock_get_per_layer_parameters(vllm_config, impl_cls):
217
+ def mock_get_per_layer_parameters(vllm_config, layer_names, impl_cls):
218
# Return mock parameters for a single layer
219
head_size = vllm_config.model_config.get_head_size()
220
return {
220
- "mock_layer":
221
+ layer_name:
222
PerLayerParameters(
223
window_left=-1, # No sliding window
224
logits_soft_cap=0.0, # No soft cap
225
sm_scale=1.0 / (head_size**0.5) # Standard scale
226
)
227
+ for layer_name in layer_names
228
}
229
230
with unittest.mock.patch(
231
'vllm.v1.attention.backends.flashinfer.get_per_layer_parameters',
232
mock_get_per_layer_parameters):
231
- builder = builder_cls(kv_cache_spec, vllm_config, device)
233
+ builder = builder_cls(kv_cache_spec, layer_names, vllm_config,
234
+ device)
235
attn_metadata = builder.build(
236
common_prefix_len=0,
237
common_attn_metadata=common_attn_metadata,
238
)
239
else:
240
# Build metadata
238
- builder = builder_cls(kv_cache_spec, vllm_config, device)
241
+ builder = builder_cls(kv_cache_spec, layer_names, vllm_config, device)
242
attn_metadata = builder.build(
243
common_prefix_len=0,
244
common_attn_metadata=common_attn_metadata,
@@ -427,8 +430,8 @@ def test_backend_correctness(batch_spec_name: str, model: str):
430
set_kv_cache_layout("HND")
431
432
backend_output = run_attention_backend(backend_name, kv_cache_spec,
430
- vllm_config, device,
431
- common_attn_metadata,
433
+ ["placeholder"], vllm_config,
434
+ device, common_attn_metadata,
435
query_vllm, key_vllm,
436
value_vllm,
437
kv_cache_for_backend)
tests/v1/spec_decode/test_eagle.py
+1
@@ -305,6 +305,7 @@ def test_propose(num_speculative_tokens):
305
_Backend.FLASH_ATTN_VLLM_V1)
306
attn_metadata_builder = attn_metadata_builder_cls(
307
kv_cache_spec=create_standard_kv_cache_spec(proposer.vllm_config),
308
+ layer_names=proposer.attn_layer_names,
309
vllm_config=proposer.vllm_config,
310
device=device,
311
)
tests/v1/worker/test_gpu_model_runner.py
+2
-1
@@ -745,7 +745,8 @@ def test_hybrid_attention_mamba_tensor_shapes(monkeypatch):
745
layer_4 = "model.layers.4.mixer"
746
layer_5 = "model.layers.5.mixer"
747
748
- with set_current_vllm_config(vllm_config):
748
+ with set_current_vllm_config(vllm_config), monkeypatch.context() as m:
749
+ m.setenv("VLLM_ATTENTION_BACKEND", "FLASHINFER")
750
hf_config = vllm_config.model_config.hf_config
751
fwd_context = {}
752
for key in [layer_0, layer_1]:
vllm/config.py
+24
-8
@@ -740,8 +740,8 @@ class ModelConfig:
740
isinstance(sliding_window, list))
741
742
if not self.disable_sliding_window and has_interleaved_attention:
743
- if (backend :=
744
- envs.VLLM_ATTENTION_BACKEND) in ("XFORMERS", "FLASHINFER"):
743
+ if not envs.VLLM_USE_V1 and (backend := envs.VLLM_ATTENTION_BACKEND
744
+ ) in ("XFORMERS", "FLASHINFER"):
745
sliding_window_len_min = get_min_sliding_window(
746
self.hf_text_config.sliding_window)
747
@@ -5065,13 +5065,29 @@ def assert_hashable(text):
5065
T = TypeVar("T")
5066
5067
5068
-def get_layers_from_vllm_config(vllm_config: VllmConfig,
5069
- layer_type: type[T]) -> dict[str, T]:
5068
+def get_layers_from_vllm_config(
5069
+ vllm_config: VllmConfig,
5070
+ layer_type: type[T],
5071
+ layer_names: Optional[list[str]] = None) -> dict[str, T]:
5072
+ """
5073
+ Get layers from the vLLM config.
5074
+
5075
+ Args:
5076
+ vllm_config: The vLLM config.
5077
+ layer_type: The type of the layer to get.
5078
+ layer_names: The names of the layers to get. If None, return all layers.
5079
+ """
5080
+
5081
+ if layer_names is None:
5082
+ layer_names = list(
5083
+ vllm_config.compilation_config.static_forward_context.keys())
5084
+
5085
+ forward_context = vllm_config.compilation_config.static_forward_context
5086
+
5087
return {
5071
- layer_name: layer
5072
- for layer_name, layer in
5073
- vllm_config.compilation_config.static_forward_context.items()
5074
- if isinstance(layer, layer_type)
5088
+ layer_name: forward_context[layer_name]
5089
+ for layer_name in layer_names
5090
+ if isinstance(forward_context[layer_name], layer_type)
5091
}
5092
5093
vllm/v1/attention/backends/cpu_attn.py
+2
-2
@@ -315,8 +315,8 @@ class TorchSDPAMetadata(AttentionMetadata):
315
316
class TorchSDPAMetadataBuilderV1(AttentionMetadataBuilder[TorchSDPAMetadata]):
317
318
- def __init__(self, kv_cache_spec: AttentionSpec, vllm_config: VllmConfig,
319
- device: torch.device) -> None:
318
+ def __init__(self, kv_cache_spec: AttentionSpec, layer_names: list[str],
319
+ vllm_config: VllmConfig, device: torch.device) -> None:
320
self.kv_cache_spec = kv_cache_spec
321
self.vllm_config = vllm_config
322
self.scheduler_config = vllm_config.scheduler_config
vllm/v1/attention/backends/flash_attn.py
+2
-2
@@ -148,8 +148,8 @@ class FlashAttentionMetadataBuilder(
148
AttentionMetadataBuilder[FlashAttentionMetadata]):
149
full_cudagraph_supported: ClassVar[bool] = get_flash_attn_version() == 3
150
151
- def __init__(self, kv_cache_spec: AttentionSpec, vllm_config: VllmConfig,
152
- device: torch.device):
151
+ def __init__(self, kv_cache_spec: AttentionSpec, layer_names: list[str],
152
+ vllm_config: VllmConfig, device: torch.device):
153
self.vllm_config = vllm_config
154
self.model_config = vllm_config.model_config
155
self.parallel_config = vllm_config.parallel_config
vllm/v1/attention/backends/flashinfer.py
+7
-11
@@ -21,10 +21,9 @@ from vllm.platforms import current_platform
21
from vllm.utils import cdiv
22
from vllm.v1.attention.backends.flash_attn import use_cascade_attention
23
from vllm.v1.attention.backends.utils import (
24
- AttentionMetadataBuilder, CommonAttentionMetadata, PerLayerParameters,
25
- get_kv_cache_layout, get_per_layer_parameters,
26
- infer_global_hyperparameters, reorder_batch_to_split_decodes_and_prefills,
27
- split_decodes_and_prefills)
24
+ AttentionMetadataBuilder, CommonAttentionMetadata, get_kv_cache_layout,
25
+ get_per_layer_parameters, infer_global_hyperparameters,
26
+ reorder_batch_to_split_decodes_and_prefills, split_decodes_and_prefills)
27
from vllm.v1.kv_cache_interface import AttentionSpec
28
29
if TYPE_CHECKING:
@@ -219,8 +218,8 @@ class FlashInferMetadata:
218
219
class FlashInferMetadataBuilder(AttentionMetadataBuilder[FlashInferMetadata]):
220
222
- def __init__(self, kv_cache_spec: AttentionSpec, vllm_config: VllmConfig,
223
- device: torch.device):
221
+ def __init__(self, kv_cache_spec: AttentionSpec, layer_names: list[str],
222
+ vllm_config: VllmConfig, device: torch.device):
223
self.device = device
224
self._workspace_buffer = None
225
self._prefill_wrapper = None # Wrapper for prefill/append
@@ -228,7 +227,8 @@ class FlashInferMetadataBuilder(AttentionMetadataBuilder[FlashInferMetadata]):
227
self._cascade_wrapper = None # Wrapper for cascade attention
228
229
# Global hyperparameters shared by all attention layers
231
- self.global_hyperparameters: Optional[PerLayerParameters] = None
230
+ self.global_hyperparameters = infer_global_hyperparameters(
231
+ get_per_layer_parameters(vllm_config, layer_names, FlashInferImpl))
232
233
self.vllm_config = vllm_config
234
self.cache_config = vllm_config.cache_config
@@ -283,10 +283,6 @@ class FlashInferMetadataBuilder(AttentionMetadataBuilder[FlashInferMetadata]):
283
284
def _plan(self, num_prefills: int, num_decodes: int,
285
attn_metadata: FlashInferMetadata):
286
- if self.global_hyperparameters is None:
287
- self.global_hyperparameters = infer_global_hyperparameters(
288
- get_per_layer_parameters(self.vllm_config, FlashInferImpl))
289
-
286
if attn_metadata.use_cascade:
287
attn_metadata.cascade_wrapper = self._get_cascade_wrapper()
288
attn_metadata.cascade_wrapper.plan(
vllm/v1/attention/backends/flex_attention.py
+2
-2
@@ -258,8 +258,8 @@ class FlexAttentionMetadata:
258
class FlexAttentionMetadataBuilder(
259
AttentionMetadataBuilder[FlexAttentionMetadata]):
260
261
- def __init__(self, kv_cache_spec: AttentionSpec, vllm_config: VllmConfig,
262
- device: torch.device):
261
+ def __init__(self, kv_cache_spec: AttentionSpec, layer_names: list[str],
262
+ vllm_config: VllmConfig, device: torch.device):
263
self.model_config = vllm_config.model_config
264
self.parallel_config = vllm_config.parallel_config
265
self.cache_config = vllm_config.cache_config
vllm/v1/attention/backends/mamba_attn.py
+2
-2
@@ -87,8 +87,8 @@ class Mamba2AttentionMetadata:
87
class Mamba2AttentionMetadataBuilder(
88
AttentionMetadataBuilder[Mamba2AttentionMetadata]):
89
90
- def __init__(self, kv_cache_spec: AttentionSpec, vllm_config: VllmConfig,
91
- device: torch.device):
90
+ def __init__(self, kv_cache_spec: AttentionSpec, layer_names: list[str],
91
+ vllm_config: VllmConfig, device: torch.device):
92
assert isinstance(kv_cache_spec, MambaSpec)
93
self.kv_cache_spec = kv_cache_spec
94
self.chunk_size = vllm_config.model_config.get_mamba_chunk_size()
vllm/v1/attention/backends/mla/common.py
+3
-1
@@ -406,6 +406,7 @@ class MLACommonMetadataBuilder(AttentionMetadataBuilder[M]):
406
407
def __init__(self,
408
kv_cache_spec: AttentionSpec,
409
+ layer_names: list[str],
410
vllm_config: VllmConfig,
411
device: torch.device,
412
metadata_cls: Optional[type[M]] = None):
@@ -471,7 +472,8 @@ class MLACommonMetadataBuilder(AttentionMetadataBuilder[M]):
472
BatchPrefillWithRaggedKVCacheWrapper] = []
473
474
self._global_hyperparameters = infer_global_hyperparameters(
474
- get_per_layer_parameters(vllm_config, MLACommonImpl))
475
+ get_per_layer_parameters(vllm_config, layer_names,
476
+ MLACommonImpl))
477
478
if self._use_cudnn_prefill:
479
self.cudnn_workspace = torch.empty(
vllm/v1/attention/backends/mla/flashmla.py
+4
-3
@@ -56,9 +56,10 @@ class FlashMLAMetadata(MLACommonMetadata[FlashMLADecodeMetadata]):
56
class FlashMLAMetadataBuilder(MLACommonMetadataBuilder[FlashMLAMetadata]):
57
full_cudagraph_supported: ClassVar[bool] = True # Decode-only
58
59
- def __init__(self, kv_cache_spec: AttentionSpec, vllm_config: VllmConfig,
60
- device: torch.device):
61
- super().__init__(kv_cache_spec, vllm_config, device, FlashMLAMetadata)
59
+ def __init__(self, kv_cache_spec: AttentionSpec, layer_names: list[str],
60
+ vllm_config: VllmConfig, device: torch.device):
61
+ super().__init__(kv_cache_spec, layer_names, vllm_config, device,
62
+ FlashMLAMetadata)
63
64
self.compilation_config = vllm_config.compilation_config
65
self.num_q_heads = vllm_config.model_config.get_num_attention_heads(
vllm/v1/attention/backends/mla/rocm_aiter_mla.py
+4
-3
@@ -66,9 +66,10 @@ class AiterMLAMetadata(MLACommonMetadata[AiterMLADecodeMetadata]):
66
class AiterMLAMetadataBuilder(MLACommonMetadataBuilder[AiterMLAMetadata]):
67
full_cudagraph_supported: ClassVar[bool] = True # decode only
68
69
- def __init__(self, kv_cache_spec: AttentionSpec, vllm_config: VllmConfig,
70
- device: torch.device):
71
- super().__init__(kv_cache_spec, vllm_config, device, AiterMLAMetadata)
69
+ def __init__(self, kv_cache_spec: AttentionSpec, layer_names: list[str],
70
+ vllm_config: VllmConfig, device: torch.device):
71
+ super().__init__(kv_cache_spec, layer_names, vllm_config, device,
72
+ AiterMLAMetadata)
73
assert self.kv_cache_spec.block_size == 1, "AITER MLA" \
74
"only supports block size 1."
75
vllm/v1/attention/backends/rocm_aiter_fa.py
+2
-2
@@ -231,8 +231,8 @@ class AiterFlashAttentionMetadataBuilder(
231
AttentionMetadataBuilder[AiterFlashAttentionMetadata]):
232
full_cudagraph_supported: ClassVar[bool] = True
233
234
- def __init__(self, kv_cache_spec: AttentionSpec, vllm_config: VllmConfig,
235
- device: torch.device):
234
+ def __init__(self, kv_cache_spec: AttentionSpec, layer_names: list[str],
235
+ vllm_config: VllmConfig, device: torch.device):
236
self.vllm_config = vllm_config
237
self.model_config = vllm_config.model_config
238
self.parallel_config = vllm_config.parallel_config
vllm/v1/attention/backends/triton_attn.py
+2
-2
@@ -59,8 +59,8 @@ class TritonAttentionMetadataBuilder(
59
AttentionMetadataBuilder[TritonAttentionMetadata]):
60
full_cudagraph_supported: ClassVar[bool] = True
61
62
- def __init__(self, kv_cache_spec: AttentionSpec, vllm_config: VllmConfig,
63
- device: torch.device):
62
+ def __init__(self, kv_cache_spec: AttentionSpec, layer_names: list[str],
63
+ vllm_config: VllmConfig, device: torch.device):
64
self.device = device
65
self.block_size = kv_cache_spec.block_size
66
self.kv_cache_spec = kv_cache_spec
vllm/v1/attention/backends/utils.py
+9
-5
@@ -70,8 +70,8 @@ class AttentionMetadataBuilder(abc.ABC, Generic[M]):
70
full_cudagraph_supported: ClassVar[bool] = False
71
72
@abstractmethod
73
- def __init__(self, kv_cache_spec: AttentionSpec, vllm_config: VllmConfig,
74
- device: torch.device):
73
+ def __init__(self, kv_cache_spec: AttentionSpec, layer_names: list[str],
74
+ vllm_config: VllmConfig, device: torch.device):
75
self.kv_cache_spec = kv_cache_spec
76
77
@abstractmethod
@@ -164,14 +164,14 @@ class PerLayerParameters:
164
165
166
def get_per_layer_parameters(
167
- vllm_config: VllmConfig,
167
+ vllm_config: VllmConfig, layer_names: list[str],
168
cls_: type['AttentionImpl']) -> dict[str, PerLayerParameters]:
169
"""
170
- Scan all attention layers and determine some hyperparameters
170
+ Scan layers in `layer_names` and determine some hyperparameters
171
to use during `plan`.
172
"""
173
174
- layers = get_layers_from_vllm_config(vllm_config, Attention)
174
+ layers = get_layers_from_vllm_config(vllm_config, Attention, layer_names)
175
per_layer_params: dict[str, PerLayerParameters] = {}
176
177
for key, layer in layers.items():
@@ -208,6 +208,10 @@ def infer_global_hyperparameters(
208
param_sets = list(per_layer_params.values())
209
global_params = param_sets[0]
210
for params in param_sets:
211
+ if params.window_left != global_params.window_left:
212
+ raise ValueError(
213
+ "Window left is not the same for all layers. One potential fix "
214
+ "is to set disable_sliding_window=True")
215
assert params == global_params, (
216
"FlashInfer backend currently only supports models in which all "
217
"layers share the same values for the following hyperparameters: "
vllm/v1/worker/gpu_model_runner.py
+8
-5
@@ -2521,7 +2521,7 @@ class GPUModelRunner(LoRAModelRunnerMixin, KVConnectorModelRunnerMixin):
2521
elapsed_time, cuda_graph_size / (1 << 30))
2522
2523
def _initialize_single_attn_backend(
2524
- self, kv_cache_spec: KVCacheSpec
2524
+ self, kv_cache_spec: KVCacheSpec, layer_names: list[str]
2525
) -> tuple[AttentionBackend, AttentionMetadataBuilder]:
2526
if isinstance(kv_cache_spec, AttentionSpec):
2527
attn_backend_i = get_attn_backend(
@@ -2551,6 +2551,7 @@ class GPUModelRunner(LoRAModelRunnerMixin, KVConnectorModelRunnerMixin):
2551
2552
attn_metadata_builder_i = attn_backend_i.get_builder_cls()(
2553
kv_cache_spec,
2554
+ layer_names,
2555
self.vllm_config,
2556
self.device,
2557
)
@@ -2574,8 +2575,9 @@ class GPUModelRunner(LoRAModelRunnerMixin, KVConnectorModelRunnerMixin):
2575
kv_cache_config.kv_cache_groups):
2576
kv_cache_spec = kv_cache_group_spec.kv_cache_spec
2577
2577
- attn_backend_i, attn_metadata_builder_i = \
2578
- self._initialize_single_attn_backend(kv_cache_spec)
2578
+ attn_backend_i, attn_metadata_builder_i = (
2579
+ self._initialize_single_attn_backend(
2580
+ kv_cache_spec, kv_cache_group_spec.layer_names))
2581
self.attn_backends.append(attn_backend_i)
2582
self.attn_metadata_builders.append(attn_metadata_builder_i)
2583
@@ -2606,8 +2608,9 @@ class GPUModelRunner(LoRAModelRunnerMixin, KVConnectorModelRunnerMixin):
2608
assert len(attn_specs) == len(attn_layers), \
2609
"All or none of the layers are expected to be encoder-only"
2610
2609
- attn_backend, attn_metadata_builder = \
2610
- self._initialize_single_attn_backend(attn_specs[0])
2611
+ attn_backend, attn_metadata_builder = (
2612
+ self._initialize_single_attn_backend(attn_specs[0],
2613
+ attn_layers.keys()))
2614
self.attn_backends.append(attn_backend)
2615
self.attn_metadata_builders.append(attn_metadata_builder)
2616
self.is_encoder_only_model = True