Split attention backends

docs/source/en/api/pipelines/qwenimage.md

@@ -108,12 +108,46 @@ pipe = QwenImageEditPlusPipeline.from_pretrained(
 image_1 = load_image("https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/diffusers/grumpy.jpg")
 image_2 = load_image("https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/diffusers/peng.png")
 image = pipe(
-    image=[image_1, image_2], 
-    prompt='''put the penguin and the cat at a game show called "Qwen Edit Plus Games"''', 
+    image=[image_1, image_2],
+    prompt='''put the penguin and the cat at a game show called "Qwen Edit Plus Games"''',
     num_inference_steps=50
 ).images[0]
 ```
 
+## Performance
+
+### torch.compile
+
+Using `torch.compile` on the transformer provides ~2.4x speedup (A100 80GB: 4.70s → 1.93s):
+
+```python
+import torch
+from diffusers import QwenImagePipeline
+
+pipe = QwenImagePipeline.from_pretrained("Qwen/Qwen-Image", torch_dtype=torch.bfloat16).to("cuda")
+pipe.transformer = torch.compile(pipe.transformer)
+
+# First call triggers compilation (~7s overhead)
+# Subsequent calls run at ~2.4x faster
+image = pipe("a cat", num_inference_steps=50).images[0]
+```
+
+### Batched Inference with Variable-Length Prompts
+
+When using classifier-free guidance (CFG) with prompts of different lengths, the pipeline properly handles padding through attention masking. This ensures padding tokens do not influence the generated output.
+
+```python
+# CFG with different prompt lengths works correctly
+image = pipe(
+    prompt="A cat",
+    negative_prompt="blurry, low quality, distorted",
+    true_cfg_scale=3.5,
+    num_inference_steps=50,
+).images[0]
+```
+
+For detailed benchmark scripts and results, see [this gist](https://gist.github.com/cdutr/bea337e4680268168550292d7819dc2f).
+
 ## QwenImagePipeline
 
 [[autodoc]] QwenImagePipeline

examples/dreambooth/train_dreambooth_lora_qwen_image.py

@@ -1513,14 +1513,12 @@ def get_sigmas(timesteps, n_dim=4, dtype=torch.float32):
                     height=model_input.shape[3],
                     width=model_input.shape[4],
                 )
-                print(f"{prompt_embeds_mask.sum(dim=1).tolist()=}")
                 model_pred = transformer(
                     hidden_states=packed_noisy_model_input,
                     encoder_hidden_states=prompt_embeds,
                     encoder_hidden_states_mask=prompt_embeds_mask,
                     timestep=timesteps / 1000,
                     img_shapes=img_shapes,
-                    txt_seq_lens=prompt_embeds_mask.sum(dim=1).tolist(),
                     return_dict=False,
                 )[0]
                 model_pred = QwenImagePipeline._unpack_latents(