[Multi Modal] Add FA3 in VIT (#24347)

Signed-off-by: wwl2755 <wangwenlong2755@gmail.com>
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Wenlong Wang 2025-09-12 06:27:24 -07:00 committed by GitHub
parent fdb09c77d6
commit 72fc8aa412
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13 changed files with 247 additions and 66 deletions

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@ -34,11 +34,11 @@ EXPECTED_MM_BEAM_SEARCH_RES = [
],
[
"The image shows a Venn diagram with three over",
"The image shows a Venn diagram with three intersect",
"This image shows a Venn diagram with three over",
],
[
"This image displays a gradient of colors ranging from",
"The image displays a gradient of colors ranging from",
"This image displays a gradient of colors forming a spectrum",
],
]

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@ -36,31 +36,52 @@ def test_mha_attn_platform(device: str):
torch.set_default_dtype(torch.float16)
if device == "cpu":
with patch("vllm.attention.selector.current_platform",
CpuPlatform()), \
patch("vllm.platforms.current_platform", CpuPlatform()):
with patch("vllm.attention.layer.current_platform", CpuPlatform()), \
patch("vllm.model_executor.models.vision.current_platform",
CpuPlatform()):
attn = MultiHeadAttention(16, 64, scale=1)
assert attn.attn_backend == _Backend.TORCH_SDPA_VLLM_V1
assert attn.attn_backend == _Backend.TORCH_SDPA
elif device == "hip":
with patch("vllm.attention.selector.current_platform",
RocmPlatform()), \
patch("vllm.platforms.current_platform", RocmPlatform()), \
patch("vllm.attention.layer.current_platform", RocmPlatform()):
with patch("vllm.attention.layer.current_platform", RocmPlatform()), \
patch("vllm.model_executor.models.vision.current_platform",
RocmPlatform()):
attn = MultiHeadAttention(16, 64, scale=1)
assert attn.attn_backend == _Backend.TORCH_SDPA
else:
with patch("vllm.attention.selector.current_platform",
CudaPlatform()), \
patch("vllm.platforms.current_platform", CudaPlatform()):
# Test CUDA with head_size=64 (divisible by 32)
# - should use vLLM's FlashAttention
with patch("vllm.attention.layer.current_platform", CudaPlatform()), \
patch("vllm.model_executor.models.vision.current_platform",
CudaPlatform()):
attn = MultiHeadAttention(16, 64, scale=1)
assert attn.attn_backend == _Backend.XFORMERS
assert attn.attn_backend == _Backend.FLASH_ATTN
with patch("vllm.attention.selector.current_platform",
# Test CUDA with head_size=72 (not divisible by 32)
# - with upstream FA not available
# - should use xformers
with patch("vllm.attention.layer.current_platform", CudaPlatform()), \
patch("vllm.model_executor.models.vision.current_platform",
CudaPlatform()), \
patch("vllm.platforms.current_platform", CudaPlatform()):
patch("vllm.attention.layer.check_upstream_fa_availability",
return_value=False):
attn = MultiHeadAttention(16, 72, scale=1)
assert attn.attn_backend == _Backend.XFORMERS
# Test CUDA with head_size=72 (not divisible by 32)
# - with upstream FA available
# - should use upstream FA
with patch("vllm.attention.layer.current_platform", CudaPlatform()), \
patch("vllm.model_executor.models.vision.current_platform",
CudaPlatform()), \
patch("vllm.attention.layer.check_upstream_fa_availability",
return_value=True), \
patch.dict('sys.modules', {'flash_attn': type('MockFlashAttn', (),
{
'flash_attn_varlen_func': lambda *args, **kwargs: None
})()}):
attn = MultiHeadAttention(16, 72, scale=1)
assert attn.attn_backend == _Backend.FLASH_ATTN
def ref_attention(
query: torch.Tensor,

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@ -23,6 +23,7 @@ from vllm.model_executor.layers.linear import UnquantizedLinearMethod
from vllm.model_executor.layers.quantization.base_config import (
QuantizationConfig)
from vllm.model_executor.layers.quantization.kv_cache import BaseKVCacheMethod
from vllm.model_executor.models.vision import get_vit_attn_backend
from vllm.platforms import _Backend, current_platform
from vllm.utils import direct_register_custom_op
@ -55,6 +56,14 @@ def check_xformers_availability():
return USE_XFORMERS_OPS
def check_upstream_fa_availability(dtype: torch.dtype):
if dtype in (torch.float16, torch.bfloat16) and current_platform.is_cuda(
) and current_platform.has_device_capability(80):
from transformers.utils import is_flash_attn_2_available
return is_flash_attn_2_available()
return False
class Attention(nn.Module, AttentionLayerBase):
"""Attention layer.
@ -349,29 +358,55 @@ class MultiHeadAttention(nn.Module):
f"divisible by num_kv_heads ({self.num_kv_heads})"
self.num_queries_per_kv = self.num_heads // self.num_kv_heads
# During model initialization, the default dtype is set as the model
# weight and activation dtype.
dtype = torch.get_default_dtype()
attn_backend = get_attn_backend(head_size,
dtype,
kv_cache_dtype=None,
block_size=16,
is_attention_free=False)
backend = backend_name_to_enum(attn_backend.get_name())
# Determine the attention backend
backend = get_vit_attn_backend(head_size=head_size, dtype=dtype)
# Some auto-selected backends can be upgraded
# to upstream flash attention if available.
# If vllm native fa is selected, we use it directly.
use_upstream_fa = False
if backend != _Backend.FLASH_ATTN and check_upstream_fa_availability(
dtype):
backend = _Backend.FLASH_ATTN
use_upstream_fa = True
if current_platform.is_rocm():
# currently, only torch_sdpa is supported on rocm
self.attn_backend = _Backend.TORCH_SDPA
else:
self.attn_backend = backend if backend in {
_Backend.TORCH_SDPA,
_Backend.TORCH_SDPA_VLLM_V1,
_Backend.XFORMERS,
_Backend.PALLAS_VLLM_V1,
_Backend.ROCM_AITER_FA,
} else current_platform.get_vit_attn_backend()
_Backend.FLASH_ATTN,
_Backend.FLASH_ATTN_VLLM_V1,
} else _Backend.TORCH_SDPA
if (self.attn_backend == _Backend.XFORMERS
and not check_xformers_availability()):
self.attn_backend = _Backend.TORCH_SDPA
if self.attn_backend in {
_Backend.FLASH_ATTN, _Backend.FLASH_ATTN_VLLM_V1
}:
if use_upstream_fa:
from flash_attn import flash_attn_varlen_func
self._flash_attn_varlen_func = flash_attn_varlen_func
else:
from vllm.vllm_flash_attn import flash_attn_varlen_func
self._flash_attn_varlen_func = flash_attn_varlen_func
logger.info_once(
f"MultiHeadAttention attn_backend: {self.attn_backend}, "
f"use_upstream_fa: {use_upstream_fa}")
def forward(
self,
query: torch.Tensor,
@ -392,7 +427,31 @@ class MultiHeadAttention(nn.Module):
key = torch.repeat_interleave(key, num_repeat, dim=2)
value = torch.repeat_interleave(value, num_repeat, dim=2)
if self.attn_backend == _Backend.XFORMERS:
if self.attn_backend in {
_Backend.FLASH_ATTN,
_Backend.FLASH_ATTN_VLLM_V1,
}:
cu_seqlens_q = torch.arange(0, (bsz + 1) * q_len,
step=q_len,
dtype=torch.int32,
device=query.device)
cu_seqlens_k = torch.arange(0, (bsz + 1) * kv_len,
step=kv_len,
dtype=torch.int32,
device=key.device)
out = self._flash_attn_varlen_func(
query.flatten(0, 1),
key.flatten(0, 1),
value.flatten(0, 1),
cu_seqlens_q=cu_seqlens_q,
cu_seqlens_k=cu_seqlens_k,
max_seqlen_q=q_len,
max_seqlen_k=kv_len,
softmax_scale=self.scale,
)
elif self.attn_backend == _Backend.XFORMERS:
from xformers import ops as xops
out = xops.memory_efficient_attention_forward(query,

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@ -34,6 +34,7 @@ import torch.nn.functional as F
from einops import rearrange, repeat
from transformers import BatchFeature
from vllm.attention.layer import check_upstream_fa_availability
from vllm.config import VllmConfig
from vllm.distributed import parallel_state
from vllm.distributed import utils as dist_utils
@ -170,7 +171,16 @@ class Ernie4_5_VisionAttention(nn.Module):
prefix=f"{prefix}.proj")
# Detect attention implementation.
self.attn_backend: _Backend = get_vit_attn_backend(support_fa=True)
self.attn_backend = get_vit_attn_backend(
head_size=self.hidden_size_per_attention_head,
dtype=torch.get_default_dtype())
self.use_upstream_fa = False
if self.attn_backend != _Backend.FLASH_ATTN and \
check_upstream_fa_availability(torch.get_default_dtype()):
self.attn_backend = _Backend.FLASH_ATTN
self.use_upstream_fa = True
if self.attn_backend not in {
_Backend.FLASH_ATTN, _Backend.TORCH_SDPA, _Backend.XFORMERS,
_Backend.ROCM_AITER_FA
@ -233,7 +243,10 @@ class Ernie4_5_VisionAttention(nn.Module):
if self.attn_backend == _Backend.ROCM_AITER_FA:
from aiter import flash_attn_varlen_func
else:
from flash_attn import flash_attn_varlen_func
if self.use_upstream_fa:
from flash_attn import flash_attn_varlen_func
else:
from vllm.vllm_flash_attn import flash_attn_varlen_func
q, k, v = (rearrange(x, "b s ... -> (b s) ...") for x in [q, k, v])
@ -457,7 +470,11 @@ class Ernie4_5_VisionTransformer(nn.Module):
), "vit's config.hidden must be equal to config.embed_dim"
self.ln = nn.LayerNorm(hidden_size, eps=1e-6)
self.attn_backend: _Backend = get_vit_attn_backend(support_fa=True)
self.attn_backend = get_vit_attn_backend(
head_size=head_dim, dtype=torch.get_default_dtype())
if self.attn_backend != _Backend.FLASH_ATTN and \
check_upstream_fa_availability(torch.get_default_dtype()):
self.attn_backend = _Backend.FLASH_ATTN
@property
def dtype(self) -> torch.dtype:

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@ -44,6 +44,7 @@ from transformers.models.glm4v.video_processing_glm4v import (
Glm4vVideoProcessor)
from transformers.video_utils import VideoMetadata
from vllm.attention.layer import check_upstream_fa_availability
from vllm.config import VllmConfig
from vllm.distributed import (get_tensor_model_parallel_world_size,
parallel_state)
@ -260,7 +261,15 @@ class Glm4vVisionAttention(nn.Module):
)
# Detect attention implementation.
self.attn_backend: _Backend = get_vit_attn_backend(support_fa=True)
self.attn_backend = get_vit_attn_backend(
head_size=self.hidden_size_per_attention_head,
dtype=torch.get_default_dtype())
self.use_upstream_fa = False
if self.attn_backend != _Backend.FLASH_ATTN and \
check_upstream_fa_availability(torch.get_default_dtype()):
self.attn_backend = _Backend.FLASH_ATTN
self.use_upstream_fa = True
if self.attn_backend not in {
_Backend.FLASH_ATTN,
_Backend.TORCH_SDPA,
@ -310,7 +319,10 @@ class Glm4vVisionAttention(nn.Module):
if self.attn_backend == _Backend.FLASH_ATTN:
# from vllm_flash_attn.flash_attn_interface import (
# flash_attn_varlen_func)
from flash_attn import flash_attn_varlen_func
if self.use_upstream_fa:
from flash_attn import flash_attn_varlen_func
else:
from vllm.vllm_flash_attn import flash_attn_varlen_func
q, k, v = (rearrange(x, "b s ... -> (b s) ...") for x in [q, k, v])
@ -715,7 +727,11 @@ class Glm4vVisionTransformer(nn.Module):
self.post_layernorm = RMSNorm(vision_config.hidden_size,
eps=vision_config.rms_norm_eps)
self.attn_backend: _Backend = get_vit_attn_backend(support_fa=True)
self.attn_backend = get_vit_attn_backend(
head_size=head_dim, dtype=torch.get_default_dtype())
if self.attn_backend != _Backend.FLASH_ATTN and \
check_upstream_fa_availability(torch.get_default_dtype()):
self.attn_backend = _Backend.FLASH_ATTN
@property
def dtype(self) -> torch.dtype:

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@ -17,6 +17,7 @@ from transformers.modeling_outputs import (BaseModelOutput,
BaseModelOutputWithPooling)
from transformers.utils import torch_int
from vllm.attention.layer import check_upstream_fa_availability
from vllm.config import VllmConfig
from vllm.distributed import get_tensor_model_parallel_world_size
from vllm.logger import init_logger
@ -374,7 +375,16 @@ class KeyeSiglipAttention(nn.Module):
)
# Detect attention implementation.
self.attn_backend: _Backend = get_vit_attn_backend(support_fa=True)
self.attn_backend = get_vit_attn_backend(
head_size=self.head_dim, dtype=torch.get_default_dtype())
self.use_upstream_fa = False
if self.attn_backend != _Backend.FLASH_ATTN and \
check_upstream_fa_availability(
torch.get_default_dtype()):
self.attn_backend = _Backend.FLASH_ATTN
self.use_upstream_fa = True
if self.attn_backend not in {_Backend.FLASH_ATTN, _Backend.XFORMERS}:
raise RuntimeError(
f"Keye-VL does not support {self.attn_backend} backend now.")
@ -428,7 +438,10 @@ class KeyeSiglipAttention(nn.Module):
)
if self.attn_backend == _Backend.FLASH_ATTN:
from flash_attn import flash_attn_varlen_func
if self.use_upstream_fa:
from flash_attn import flash_attn_varlen_func
else:
from vllm.vllm_flash_attn import flash_attn_varlen_func
q, k, v = (rearrange(x, "b s ... -> (b s) ...") for x in [q, k, v])

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@ -38,6 +38,7 @@ from transformers.models.qwen2_5_vl import Qwen2_5_VLProcessor
from transformers.models.qwen2_5_vl.configuration_qwen2_5_vl import (
Qwen2_5_VLConfig, Qwen2_5_VLVisionConfig)
from vllm.attention.layer import check_upstream_fa_availability
from vllm.config import VllmConfig
from vllm.distributed import parallel_state
from vllm.distributed import utils as dist_utils
@ -298,7 +299,16 @@ class Qwen2_5_VisionAttention(nn.Module):
disable_tp=use_data_parallel)
# Detect attention implementation.
self.attn_backend: _Backend = get_vit_attn_backend(support_fa=True)
self.attn_backend = get_vit_attn_backend(
head_size=self.hidden_size_per_attention_head,
dtype=torch.get_default_dtype())
self.use_upstream_fa = False
if self.attn_backend != _Backend.FLASH_ATTN and \
check_upstream_fa_availability(
torch.get_default_dtype()):
self.attn_backend = _Backend.FLASH_ATTN
self.use_upstream_fa = True
if self.attn_backend not in {
_Backend.FLASH_ATTN, _Backend.TORCH_SDPA, _Backend.XFORMERS,
_Backend.ROCM_AITER_FA
@ -359,7 +369,10 @@ class Qwen2_5_VisionAttention(nn.Module):
if self.attn_backend == _Backend.ROCM_AITER_FA:
from aiter import flash_attn_varlen_func
else:
from flash_attn import flash_attn_varlen_func
if self.use_upstream_fa:
from flash_attn import flash_attn_varlen_func
else:
from vllm.vllm_flash_attn import flash_attn_varlen_func
q, k, v = (rearrange(x, "b s ... -> (b s) ...") for x in [q, k, v])
@ -628,7 +641,12 @@ class Qwen2_5_VisionTransformer(nn.Module):
prefix=f"{prefix}.merger",
use_data_parallel=use_data_parallel,
)
self.attn_backend: _Backend = get_vit_attn_backend(support_fa=True)
self.attn_backend = get_vit_attn_backend(
head_size=head_dim, dtype=torch.get_default_dtype())
if self.attn_backend != _Backend.FLASH_ATTN and \
check_upstream_fa_availability(
torch.get_default_dtype()):
self.attn_backend = _Backend.FLASH_ATTN
@property
def dtype(self) -> torch.dtype:

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@ -41,6 +41,7 @@ from transformers.models.qwen2_vl.image_processing_qwen2_vl import smart_resize
from transformers.models.qwen2_vl.video_processing_qwen2_vl import (
Qwen2VLVideoProcessor)
from vllm.attention.layer import check_upstream_fa_availability
from vllm.config import VllmConfig
from vllm.distributed import parallel_state, tensor_model_parallel_all_gather
from vllm.distributed import utils as dist_utils
@ -314,7 +315,16 @@ class Qwen2VisionAttention(nn.Module):
prefix=f"{prefix}.proj")
# Detect attention implementation.
self.attn_backend: _Backend = get_vit_attn_backend(support_fa=True)
self.attn_backend = get_vit_attn_backend(
head_size=self.hidden_size_per_attention_head,
dtype=torch.get_default_dtype())
self.use_upstream_fa = False
if self.attn_backend != _Backend.FLASH_ATTN and \
check_upstream_fa_availability(
torch.get_default_dtype()):
self.attn_backend = _Backend.FLASH_ATTN
self.use_upstream_fa = True
if self.attn_backend not in {
_Backend.FLASH_ATTN, _Backend.TORCH_SDPA, _Backend.XFORMERS,
_Backend.ROCM_AITER_FA
@ -374,7 +384,10 @@ class Qwen2VisionAttention(nn.Module):
if self.attn_backend == _Backend.ROCM_AITER_FA:
from aiter import flash_attn_varlen_func
else:
from flash_attn import flash_attn_varlen_func
if self.use_upstream_fa:
from flash_attn import flash_attn_varlen_func
else:
from vllm.vllm_flash_attn import flash_attn_varlen_func
q, k, v = (rearrange(x, "b s ... -> (b s) ...") for x in [q, k, v])
@ -628,7 +641,12 @@ class Qwen2VisionTransformer(nn.Module):
quant_config=quant_config,
prefix=f"{prefix}.merger",
)
self.attn_backend: _Backend = get_vit_attn_backend(support_fa=True)
self.attn_backend = get_vit_attn_backend(
head_size=head_dim, dtype=torch.get_default_dtype())
if self.attn_backend != _Backend.FLASH_ATTN and \
check_upstream_fa_availability(
torch.get_default_dtype()):
self.attn_backend = _Backend.FLASH_ATTN
@property
def dtype(self) -> torch.dtype:

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@ -13,6 +13,7 @@ from torch.nn import functional as F
from transformers import Siglip2VisionConfig
from transformers.configuration_utils import PretrainedConfig
from vllm.attention.layer import check_upstream_fa_availability
from vllm.config import QuantizationConfig
from vllm.distributed import divide, get_tensor_model_parallel_world_size
from vllm.model_executor.layers.activation import get_act_fn
@ -236,7 +237,15 @@ class Siglip2Attention(nn.Module):
self.use_rope = config.use_rope
# Detect attention implementation.
self.attn_backend: _Backend = get_vit_attn_backend(support_fa=True)
self.attn_backend = get_vit_attn_backend(
head_size=self.head_dim, dtype=torch.get_default_dtype())
self.use_upstream_fa = False
if self.attn_backend != _Backend.FLASH_ATTN and \
check_upstream_fa_availability(
torch.get_default_dtype()):
self.attn_backend = _Backend.FLASH_ATTN
self.use_upstream_fa = True
if self.attn_backend not in {
_Backend.FLASH_ATTN, _Backend.TORCH_SDPA,
_Backend.ROCM_AITER_FA
@ -280,7 +289,10 @@ class Siglip2Attention(nn.Module):
if self.attn_backend == _Backend.ROCM_AITER_FA:
from aiter import flash_attn_varlen_func
else:
from flash_attn import flash_attn_varlen_func
if self.use_upstream_fa:
from flash_attn import flash_attn_varlen_func
else:
from vllm.vllm_flash_attn import flash_attn_varlen_func
attn_output = flash_attn_varlen_func(
queries, keys, values, cu_seqlens, cu_seqlens, max_seqlen,
max_seqlen).reshape(seq_length, -1)

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@ -7,7 +7,6 @@ from typing import Final, Generic, Optional, Protocol, TypeVar, Union
import torch
from transformers import PretrainedConfig
from vllm.attention.selector import get_env_variable_attn_backend
from vllm.logger import init_logger
from vllm.platforms import _Backend, current_platform
@ -68,17 +67,18 @@ def get_vision_encoder_info(
raise NotImplementedError(msg)
def get_vit_attn_backend(support_fa: bool = False) -> _Backend:
def get_vit_attn_backend(head_size: int, dtype: torch.dtype) -> _Backend:
"""
Get the available attention backend for Vision Transformer.
"""
# TODO(Isotr0py): Remove `support_fa` after support FA for all ViTs attn.
# Lazy import to avoid circular dependency
from vllm.attention.selector import get_env_variable_attn_backend
selected_backend: Optional[_Backend] = get_env_variable_attn_backend()
if selected_backend is not None:
return selected_backend
return current_platform.get_vit_attn_backend(support_fa)
return current_platform.get_vit_attn_backend(head_size, dtype)
def resolve_visual_encoder_outputs(
@ -122,4 +122,4 @@ def resolve_visual_encoder_outputs(
uses_last_layer = feature_sample_layers[-1] in (len(hs_pool) - 1, -1)
if post_layer_norm is not None and uses_last_layer:
hs_pool[-1] = post_layer_norm(encoder_outputs)
return torch.cat(hs_pool, dim=-1)
return torch.cat(hs_pool, dim=-1)

View File

@ -209,18 +209,24 @@ class CudaPlatformBase(Platform):
return torch.cuda.max_memory_allocated(device)
@classmethod
def get_vit_attn_backend(cls, support_fa: bool = False) -> _Backend:
if cls.has_device_capability(80) and support_fa:
from transformers.utils import is_flash_attn_2_available
if is_flash_attn_2_available():
def get_vit_attn_backend(cls, head_size: int,
dtype: torch.dtype) -> _Backend:
if dtype not in (torch.float16, torch.bfloat16):
return _Backend.XFORMERS
if cls.has_device_capability(80):
FLASH_ATTN_V1 = "vllm.v1.attention.backends.flash_attn.FlashAttentionBackend" # noqa: E501
from vllm.attention.selector import is_attn_backend_supported
is_default_fa_supported = is_attn_backend_supported(
FLASH_ATTN_V1, head_size, dtype, allow_import_error=False)
if is_default_fa_supported:
return _Backend.FLASH_ATTN
logger.warning_once(
"Current `vllm-flash-attn` has a bug inside vision "
"module, so we use xformers backend instead. You can "
"run `pip install flash-attn` to use flash-attention "
"backend.")
# Fallback for Volta/Turing GPUs or FA not supported
return _Backend.XFORMERS
else:
# Fallback to XFORMERS
return _Backend.XFORMERS
else:
# Fallback for Volta/Turing GPUs or FA not supported
return _Backend.XFORMERS
@classmethod
def get_attn_backend_cls(cls, selected_backend, head_size, dtype,

View File

@ -192,7 +192,8 @@ class Platform:
return device_id
@classmethod
def get_vit_attn_backend(cls, support_fa: bool = False) -> _Backend:
def get_vit_attn_backend(cls, head_size: int,
dtype: torch.dtype) -> _Backend:
return _Backend.TORCH_SDPA
@classmethod

View File

@ -175,15 +175,15 @@ class RocmPlatform(Platform):
]
@classmethod
def get_vit_attn_backend(cls, support_fa: bool = False) -> _Backend:
if support_fa:
if (envs.VLLM_ROCM_USE_AITER and envs.VLLM_ROCM_USE_AITER_MHA
and on_gfx9()):
# Note: AITER FA is only supported for Qwen-VL models.
# TODO: Add support for other VL models in their model class.
return _Backend.ROCM_AITER_FA
if on_gfx9():
return _Backend.FLASH_ATTN
def get_vit_attn_backend(cls, head_size: int,
dtype: torch.dtype) -> _Backend:
if (envs.VLLM_ROCM_USE_AITER and envs.VLLM_ROCM_USE_AITER_MHA
and on_gfx9()):
# Note: AITER FA is only supported for Qwen-VL models.
# TODO: Add support for other VL models in their model class.
return _Backend.ROCM_AITER_FA
if on_gfx9():
return _Backend.FLASH_ATTN
return _Backend.TORCH_SDPA
@classmethod