Add support for Qwen2-VL-based embedding models (#2055)

README.md

@@ -37,7 +37,7 @@ The core features include:
 
 - **Fast Backend Runtime**: Provides efficient serving with RadixAttention for prefix caching, jump-forward constrained decoding, continuous batching, token attention (paged attention), tensor parallelism, FlashInfer kernels, chunked prefill, and quantization (INT4/FP8/AWQ/GPTQ).
 - **Flexible Frontend Language**: Offers an intuitive interface for programming LLM applications, including chained generation calls, advanced prompting, control flow, multi-modal inputs, parallelism, and external interactions.
-- **Extensive Model Support**: Supports a wide range of generative models (Llama, Gemma, Mistral, QWen, DeepSeek, LLaVA, etc.), embedding models (e5-mistral, gte) and reward models (Skywork), with easy extensibility for integrating new models.
+- **Extensive Model Support**: Supports a wide range of generative models (Llama, Gemma, Mistral, QWen, DeepSeek, LLaVA, etc.), embedding models (e5-mistral, gte, mcdse) and reward models (Skywork), with easy extensibility for integrating new models.
 - **Active Community**: SGLang is open-source and backed by an active community with industry adoption.
 
 ## Getting Started

python/sglang/srt/models/qwen2_vl.py

@@ -44,6 +44,7 @@ from sglang.srt.layers.attention.triton_ops.prefill_attention import (
 )
 from sglang.srt.layers.linear import ColumnParallelLinear, RowParallelLinear
 from sglang.srt.layers.logits_processor import LogitsProcessor
+from sglang.srt.layers.pooler import Pooler, PoolingType
 from sglang.srt.layers.quantization.base_config import QuantizationConfig
 from sglang.srt.layers.vocab_parallel_embedding import ParallelLMHead
 from sglang.srt.managers.schedule_batch import ImageInputs
@@ -559,6 +560,7 @@ class Qwen2VLForConditionalGeneration(nn.Module):
             )
 
         self.logits_processor = LogitsProcessor(config)
+        self.pooler = Pooler(pooling_type=PoolingType.LAST, normalize=True)
 
     def _process_image_input(self, image_input: Qwen2VLImageInputs) -> torch.Tensor:
         pixel_values = image_input["pixel_values"].type(self.visual.dtype)
@@ -577,6 +579,7 @@ class Qwen2VLForConditionalGeneration(nn.Module):
         input_ids: torch.Tensor,
         positions: torch.Tensor,
         forward_batch: ForwardBatch,
+        get_embedding: bool = False,
     ):
         """Run forward pass for Qwen2-VL.
 
@@ -599,8 +602,8 @@ class Qwen2VLForConditionalGeneration(nn.Module):
             image_inputs = [
                 img for img in forward_batch.image_inputs if img is not None
             ]
-
-        positions = forward_batch.mrope_positions
+        if getattr(self.config, "rope_scaling", {}).get("type", None) == "mrope":
+            positions = forward_batch.mrope_positions
         if (
             forward_batch.forward_mode.is_decode()
             or image_inputs is None
@@ -655,9 +658,13 @@ class Qwen2VLForConditionalGeneration(nn.Module):
             forward_batch=forward_batch,
             input_embeds=inputs_embeds,
         )
-        return self.logits_processor(
-            input_ids, hidden_states, self.lm_head.weight, forward_batch
-        )
+
+        if not get_embedding:
+            return self.logits_processor(
+                input_ids, hidden_states, self.lm_head.weight, forward_batch
+            )
+        else:
+            return self.pooler(hidden_states, forward_batch)
 
     def load_weights(self, weights: Iterable[Tuple[str, torch.Tensor]]):
         stacked_params_mapping = [

python/sglang/test/runners.py

@@ -58,6 +58,28 @@ def get_top_logprobs(logits, k):
     return logprobs
 
 
+def _get_sentence_transformer_embedding_model(model_path, torch_dtype):
+    from sentence_transformers import SentenceTransformer
+    from sentence_transformers.util import is_sentence_transformer_model
+
+    if is_sentence_transformer_model(model_path):
+        model = SentenceTransformer(
+            model_path,
+            model_kwargs={"torch_dtype": torch_dtype},
+        )
+    else:  # if no pre-trained sentence-transformers model
+        from sentence_transformers import models
+
+        word_embedding_model = models.Transformer(model_path).to(dtype=torch_dtype)
+        pooling_model = models.Pooling(
+            word_embedding_model.get_word_embedding_dimension(),
+            pooling_mode="lasttoken",
+        )
+        model = SentenceTransformer(modules=[word_embedding_model, pooling_model])
+
+    return model.cuda()
+
+
 @dataclass
 class ModelOutput:
     output_strs: List[str] = None
@@ -114,12 +136,9 @@ class HFRunner:
                 low_cpu_mem_usage=True,
             ).cuda()
         elif self.model_type == "embedding":
-            from sentence_transformers import SentenceTransformer
-
-            self.model = SentenceTransformer(
-                model_path,
-                model_kwargs={"torch_dtype": torch_dtype},
-            ).cuda()
+            self.model = _get_sentence_transformer_embedding_model(
+                model_path, torch_dtype
+            )
         elif self.model_type == "reward":
             from transformers import AutoModelForSequenceClassification
 

test/srt/models/test_embedding_models.py

@@ -25,6 +25,7 @@ from sglang.test.test_utils import get_similarities
 MODELS = [
     ("Alibaba-NLP/gte-Qwen2-1.5B-instruct", 1, 1e-5),
     ("intfloat/e5-mistral-7b-instruct", 1, 1e-5),
+    ("marco/mcdse-2b-v1", 1, 1e-5),
 ]
 TORCH_DTYPES = [torch.float16]