Files changed (3) hide show
  1. README.md +1 -1
  2. qwenimage/qwen_fa3_processor.py +60 -151
  3. requirements.txt +1 -1
README.md CHANGED
@@ -4,7 +4,7 @@ emoji: 🔥
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  colorFrom: indigo
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  colorTo: gray
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  sdk: gradio
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- sdk_version: 6.14.0
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  app_file: app.py
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  pinned: true
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  license: apache-2.0
 
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  colorFrom: indigo
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  colorTo: gray
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  sdk: gradio
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+ sdk_version: 6.3.0
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  app_file: app.py
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  pinned: true
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  license: apache-2.0
qwenimage/qwen_fa3_processor.py CHANGED
@@ -1,183 +1,89 @@
1
  """
2
  Paired with a good language model. Thanks!
3
-
4
- FA3 is currently broken on Blackwell (sm_100) GPUs; this module detects that
5
- at import time and falls back to PyTorch scaled-dot-product attention (SDPA)
6
- automatically. The public class name / call signature are unchanged.
7
  """
8
 
9
  import torch
10
- import torch.nn.functional as F
11
  from typing import Optional, Tuple
12
  from diffusers.models.transformers.transformer_qwenimage import apply_rotary_emb_qwen
13
 
14
-
15
- # ---------------------------------------------------------------------------
16
- # FA3 availability check
17
- # ---------------------------------------------------------------------------
18
-
19
- def _is_blackwell() -> bool:
20
- """Return True when the current default CUDA device is an sm_100 (Blackwell) GPU."""
21
- if not torch.cuda.is_available():
22
- return False
23
- cap = torch.cuda.get_device_capability()
24
- # Blackwell compute capability 10.x (sm_100)
25
- return cap[0] >= 10
26
-
27
-
28
- _fa3_available: bool = False
29
- _fa3_unavailable_reason: str = ""
30
- _flash_attn_func = None
31
-
32
- if _is_blackwell():
33
- _fa3_unavailable_reason = (
34
- "FlashAttention-3 is not yet supported on Blackwell (sm_100) GPUs. "
35
- "Falling back to scaled-dot-product attention (SDPA)."
36
- )
37
- else:
38
- try:
39
- from kernels import get_kernel
40
- _k = get_kernel("kernels-community/vllm-flash-attn3")
41
- _flash_attn_func = _k.flash_attn_func
42
- _fa3_available = True
43
- except Exception as e:
44
- _fa3_unavailable_reason = (
45
- "FlashAttention-3 via Hugging Face `kernels` is unavailable. "
46
- f"Tried `get_kernel('kernels-community/vllm-flash-attn3')` and failed with:\n{e}\n"
47
- "Falling back to scaled-dot-product attention (SDPA)."
48
  )
49
 
50
-
51
- # ---------------------------------------------------------------------------
52
- # FA3 custom op (registered only when the kernel loaded successfully)
53
- # ---------------------------------------------------------------------------
54
-
55
- if _fa3_available:
56
- @torch.library.custom_op("flash::flash_attn_func", mutates_args=())
57
- def flash_attn_func(
58
- q: torch.Tensor, k: torch.Tensor, v: torch.Tensor, causal: bool = False
59
- ) -> torch.Tensor:
60
- # _flash_attn_func returns (output, softmax_lse); we only need output.
61
- output, _lse = _flash_attn_func(q, k, v, causal=causal)
62
- return output
63
-
64
- @flash_attn_func.register_fake
65
- def _flash_attn_func_fake(q, k, v, causal=False):
66
- # output shape mirrors q: (batch, seq_len, num_heads, head_dim)
67
- return torch.empty_like(q).contiguous()
68
-
69
- else:
70
- # Provide a stub so call-sites that import the symbol don't break at
71
- # module load; the processor will route around it at runtime.
72
- def flash_attn_func(
73
- q: torch.Tensor, k: torch.Tensor, v: torch.Tensor, causal: bool = False
74
- ) -> torch.Tensor:
75
- raise RuntimeError(_fa3_unavailable_reason)
76
-
77
-
78
- # ---------------------------------------------------------------------------
79
- # SDPA fallback helper
80
- # ---------------------------------------------------------------------------
81
-
82
- def _sdpa_attention(
83
- q: torch.Tensor,
84
- k: torch.Tensor,
85
- v: torch.Tensor,
86
- causal: bool = False,
87
  ) -> torch.Tensor:
88
- """
89
- Scaled dot-product attention using torch.nn.functional.scaled_dot_product_attention.
90
-
91
- Input / output layout: (B, S, H, D_h) — same as the FA3 kernel.
92
- """
93
- # SDPA expects (B, H, S, D_h)
94
- q = q.transpose(1, 2)
95
- k = k.transpose(1, 2)
96
- v = v.transpose(1, 2)
97
 
98
- out = F.scaled_dot_product_attention(q, k, v, is_causal=causal)
 
 
 
 
 
 
99
 
100
- # Back to (B, S, H, D_h)
101
- return out.transpose(1, 2)
102
-
103
-
104
- # ---------------------------------------------------------------------------
105
- # Attention processor
106
- # ---------------------------------------------------------------------------
107
 
108
  class QwenDoubleStreamAttnProcessorFA3:
109
  """
110
- Attention processor for the Qwen double-stream architecture.
111
-
112
- Preferred backend: vLLM FlashAttention-3 via Hugging Face ``kernels``.
113
- Automatic fallback: PyTorch ``scaled_dot_product_attention`` (SDPA) when
114
- FA3 is unavailable — e.g. on Blackwell (sm_100) GPUs where FA3 is not yet
115
- supported, or when the ``kernels`` package is absent.
116
-
117
- Notes / limitations
118
- -------------------
119
- - Arbitrary attention masks are not supported on the FA3 path. Pass
120
- ``attention_mask=None`` (the default) to stay on the fast path.
121
- - On the SDPA path, ``attention_mask`` is likewise ignored; add explicit
122
- support here if you need it.
123
- - ``encoder_hidden_states`` (text stream) is required.
124
  """
125
 
126
- _attention_backend: str # set in __init__ after capability detection
127
 
128
  def __init__(self):
129
- if _fa3_available:
130
- self._attention_backend = "fa3"
131
- else:
132
- import warnings
133
- warnings.warn(
134
- f"QwenDoubleStreamAttnProcessorFA3: {_fa3_unavailable_reason}",
135
- stacklevel=2,
136
- )
137
- self._attention_backend = "sdpa"
138
-
139
- def _attend(
140
- self,
141
- q: torch.Tensor,
142
- k: torch.Tensor,
143
- v: torch.Tensor,
144
- causal: bool = False,
145
- ) -> torch.Tensor:
146
- """Dispatch to FA3 or SDPA depending on what is available."""
147
- if self._attention_backend == "fa3":
148
- return flash_attn_func(q, k, v, causal=causal)
149
- return _sdpa_attention(q, k, v, causal=causal)
150
 
151
  @torch.no_grad()
152
  def __call__(
153
  self,
154
- attn,
155
- hidden_states: torch.FloatTensor, # (B, S_img, D_model)
156
- encoder_hidden_states: torch.FloatTensor = None, # (B, S_txt, D_model)
157
- encoder_hidden_states_mask: torch.FloatTensor = None, # unused
158
- attention_mask: Optional[torch.FloatTensor] = None, # unsupported on FA3 path
159
- image_rotary_emb: Optional[Tuple[torch.Tensor, torch.Tensor]] = None,
160
  ) -> Tuple[torch.FloatTensor, torch.FloatTensor]:
161
-
162
  if encoder_hidden_states is None:
163
- raise ValueError(
164
- "QwenDoubleStreamAttnProcessorFA3 requires encoder_hidden_states (text stream)."
165
- )
166
- if attention_mask is not None and self._attention_backend == "fa3":
167
- raise NotImplementedError(
168
- "attention_mask is not supported on the FA3 path. "
169
- "Either drop the mask or let the processor fall back to SDPA."
170
- )
171
 
172
  B, S_img, _ = hidden_states.shape
173
  S_txt = encoder_hidden_states.shape[1]
174
 
175
- # ---- QKV projections ----
176
- img_q = attn.to_q(hidden_states)
177
  img_k = attn.to_k(hidden_states)
178
  img_v = attn.to_v(hidden_states)
179
 
180
- txt_q = attn.add_q_proj(encoder_hidden_states)
 
181
  txt_k = attn.add_k_proj(encoder_hidden_states)
182
  txt_v = attn.add_v_proj(encoder_hidden_states)
183
 
@@ -191,7 +97,7 @@ class QwenDoubleStreamAttnProcessorFA3:
191
  txt_k = txt_k.unflatten(-1, (H, -1))
192
  txt_v = txt_v.unflatten(-1, (H, -1))
193
 
194
- # ---- Q/K normalization ----
195
  if getattr(attn, "norm_q", None) is not None:
196
  img_q = attn.norm_q(img_q)
197
  if getattr(attn, "norm_k", None) is not None:
@@ -204,22 +110,25 @@ class QwenDoubleStreamAttnProcessorFA3:
204
  # ---- RoPE (Qwen variant) ----
205
  if image_rotary_emb is not None:
206
  img_freqs, txt_freqs = image_rotary_emb
 
207
  img_q = apply_rotary_emb_qwen(img_q, img_freqs, use_real=False)
208
  img_k = apply_rotary_emb_qwen(img_k, img_freqs, use_real=False)
209
  txt_q = apply_rotary_emb_qwen(txt_q, txt_freqs, use_real=False)
210
  txt_k = apply_rotary_emb_qwen(txt_k, txt_freqs, use_real=False)
211
 
212
  # ---- Joint attention over [text, image] along sequence axis ----
213
- q = torch.cat([txt_q, img_q], dim=1) # (B, S_txt + S_img, H, D_h)
 
214
  k = torch.cat([txt_k, img_k], dim=1)
215
  v = torch.cat([txt_v, img_v], dim=1)
216
 
217
- out = self._attend(q, k, v, causal=False) # (B, S_total, H, D_h)
 
218
 
219
  # ---- Back to (B, S, D_model) ----
220
  out = out.flatten(2, 3).to(q.dtype)
221
 
222
- # ---- Split text / image segments ----
223
  txt_attn_out = out[:, :S_txt, :]
224
  img_attn_out = out[:, S_txt:, :]
225
 
 
1
  """
2
  Paired with a good language model. Thanks!
 
 
 
 
3
  """
4
 
5
  import torch
 
6
  from typing import Optional, Tuple
7
  from diffusers.models.transformers.transformer_qwenimage import apply_rotary_emb_qwen
8
 
9
+ try:
10
+ from kernels import get_kernel
11
+ _k = get_kernel("kernels-community/vllm-flash-attn3")
12
+ _flash_attn_func = _k.flash_attn_func
13
+ except Exception as e:
14
+ _flash_attn_func = None
15
+ _kernels_err = e
16
+
17
+
18
+ def _ensure_fa3_available():
19
+ if _flash_attn_func is None:
20
+ raise ImportError(
21
+ "FlashAttention-3 via Hugging Face `kernels` is required. "
22
+ "Tried `get_kernel('kernels-community/vllm-flash-attn3')` and failed with:\n"
23
+ f"{_kernels_err}"
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
24
  )
25
 
26
+ @torch.library.custom_op("flash::flash_attn_func", mutates_args=())
27
+ def flash_attn_func(
28
+ q: torch.Tensor, k: torch.Tensor, v: torch.Tensor, causal: bool = False
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
29
  ) -> torch.Tensor:
30
+ outputs, lse = _flash_attn_func(q, k, v, causal=causal)
31
+ return outputs
 
 
 
 
 
 
 
32
 
33
+ @flash_attn_func.register_fake
34
+ def _(q, k, v, **kwargs):
35
+ # two outputs:
36
+ # 1. output: (batch, seq_len, num_heads, head_dim)
37
+ # 2. softmax_lse: (batch, num_heads, seq_len) with dtype=torch.float32
38
+ meta_q = torch.empty_like(q).contiguous()
39
+ return meta_q #, q.new_empty((q.size(0), q.size(2), q.size(1)), dtype=torch.float32)
40
 
 
 
 
 
 
 
 
41
 
42
  class QwenDoubleStreamAttnProcessorFA3:
43
  """
44
+ FA3-based attention processor for Qwen double-stream architecture.
45
+ Computes joint attention over concatenated [text, image] streams using vLLM FlashAttention-3
46
+ accessed via Hugging Face `kernels`.
47
+
48
+ Notes / limitations:
49
+ - General attention masks are not supported here (FA3 path). `is_causal=False` and no arbitrary mask.
50
+ - Optional windowed attention / sink tokens / softcap can be plumbed through if you use those features.
51
+ - Expects an available `apply_rotary_emb_qwen` in scope (same as your non-FA3 processor).
 
 
 
 
 
 
52
  """
53
 
54
+ _attention_backend = "fa3" # for parity with your other processors, not used internally
55
 
56
  def __init__(self):
57
+ _ensure_fa3_available()
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
58
 
59
  @torch.no_grad()
60
  def __call__(
61
  self,
62
+ attn, # Attention module with to_q/to_k/to_v/add_*_proj, norms, to_out, to_add_out, and .heads
63
+ hidden_states: torch.FloatTensor, # (B, S_img, D_model) image stream
64
+ encoder_hidden_states: torch.FloatTensor = None, # (B, S_txt, D_model) text stream
65
+ encoder_hidden_states_mask: torch.FloatTensor = None, # unused in FA3 path
66
+ attention_mask: Optional[torch.FloatTensor] = None, # unused in FA3 path
67
+ image_rotary_emb: Optional[Tuple[torch.Tensor, torch.Tensor]] = None, # (img_freqs, txt_freqs)
68
  ) -> Tuple[torch.FloatTensor, torch.FloatTensor]:
 
69
  if encoder_hidden_states is None:
70
+ raise ValueError("QwenDoubleStreamAttnProcessorFA3 requires encoder_hidden_states (text stream).")
71
+ if attention_mask is not None:
72
+ # FA3 kernel path here does not consume arbitrary masks; fail fast to avoid silent correctness issues.
73
+ raise NotImplementedError("attention_mask is not supported in this FA3 implementation.")
74
+
75
+ _ensure_fa3_available()
 
 
76
 
77
  B, S_img, _ = hidden_states.shape
78
  S_txt = encoder_hidden_states.shape[1]
79
 
80
+ # ---- QKV projections (image/sample stream) ----
81
+ img_q = attn.to_q(hidden_states) # (B, S_img, D)
82
  img_k = attn.to_k(hidden_states)
83
  img_v = attn.to_v(hidden_states)
84
 
85
+ # ---- QKV projections (text/context stream) ----
86
+ txt_q = attn.add_q_proj(encoder_hidden_states) # (B, S_txt, D)
87
  txt_k = attn.add_k_proj(encoder_hidden_states)
88
  txt_v = attn.add_v_proj(encoder_hidden_states)
89
 
 
97
  txt_k = txt_k.unflatten(-1, (H, -1))
98
  txt_v = txt_v.unflatten(-1, (H, -1))
99
 
100
+ # ---- Q/K normalization (per your module contract) ----
101
  if getattr(attn, "norm_q", None) is not None:
102
  img_q = attn.norm_q(img_q)
103
  if getattr(attn, "norm_k", None) is not None:
 
110
  # ---- RoPE (Qwen variant) ----
111
  if image_rotary_emb is not None:
112
  img_freqs, txt_freqs = image_rotary_emb
113
+ # expects tensors shaped (B, S, H, D_h)
114
  img_q = apply_rotary_emb_qwen(img_q, img_freqs, use_real=False)
115
  img_k = apply_rotary_emb_qwen(img_k, img_freqs, use_real=False)
116
  txt_q = apply_rotary_emb_qwen(txt_q, txt_freqs, use_real=False)
117
  txt_k = apply_rotary_emb_qwen(txt_k, txt_freqs, use_real=False)
118
 
119
  # ---- Joint attention over [text, image] along sequence axis ----
120
+ # Shapes: (B, S_total, H, D_h)
121
+ q = torch.cat([txt_q, img_q], dim=1)
122
  k = torch.cat([txt_k, img_k], dim=1)
123
  v = torch.cat([txt_v, img_v], dim=1)
124
 
125
+ # FlashAttention-3 path expects (B, S, H, D_h) and returns (out, softmax_lse)
126
+ out = flash_attn_func(q, k, v, causal=False) # out: (B, S_total, H, D_h)
127
 
128
  # ---- Back to (B, S, D_model) ----
129
  out = out.flatten(2, 3).to(q.dtype)
130
 
131
+ # Split back to text / image segments
132
  txt_attn_out = out[:, :S_txt, :]
133
  img_attn_out = out[:, S_txt:, :]
134
 
requirements.txt CHANGED
@@ -9,6 +9,6 @@ supervision
9
  kernels
10
  spaces
11
  hf_xet
12
- torch==2.11.0
13
  numpy
14
  av
 
9
  kernels
10
  spaces
11
  hf_xet
12
+ torch
13
  numpy
14
  av