[Model] Add PaliGemma (vllm-project#5189)

Co-authored-by: Woosuk Kwon <woosuk.kwon@berkeley.edu>

docs/source/models/supported_models.rst

@@ -186,6 +186,10 @@ Vision Language Models
     - LLaVA-NeXT
     - :code:`llava-hf/llava-v1.6-mistral-7b-hf`, :code:`llava-hf/llava-v1.6-vicuna-7b-hf`, etc.
     -
+  * - :code:`PaliGemmaForConditionalGeneration`
+    - PaliGemma
+    - :code:`google/paligemma-3b-pt-224`, :code:`google/paligemma-3b-mix-224`, etc.
+    - 
   * - :code:`Phi3VForCausalLM`
     - Phi-3-Vision
     - :code:`microsoft/Phi-3-vision-128k-instruct`, etc.

examples/paligemma_example.py

@@ -0,0 +1,52 @@
+import os
+import subprocess
+
+from PIL import Image
+
+from vllm import LLM
+
+# The assets are located at `s3://air-example-data-2/vllm_opensource_llava/`.
+# You can use `.buildkite/download-images.sh` to download them
+
+
+def run_paligemma():
+    llm = LLM(model="google/paligemma-3b-mix-224")
+
+    prompt = "caption es"
+
+    image = Image.open("images/stop_sign.jpg")
+
+    outputs = llm.generate({
+        "prompt": prompt,
+        "multi_modal_data": {
+            "image": image
+        },
+    })
+
+    for o in outputs:
+        generated_text = o.outputs[0].text
+        print(generated_text)
+
+
+def main():
+    run_paligemma()
+
+
+if __name__ == "__main__":
+    # Download from s3
+    s3_bucket_path = "s3://air-example-data-2/vllm_opensource_llava/"
+    local_directory = "images"
+
+    # Make sure the local directory exists or create it
+    os.makedirs(local_directory, exist_ok=True)
+
+    # Use AWS CLI to sync the directory, assume anonymous access
+    subprocess.check_call([
+        "aws",
+        "s3",
+        "sync",
+        s3_bucket_path,
+        local_directory,
+        "--no-sign-request",
+    ])
+    main()

tests/models/test_paligemma.py

@@ -0,0 +1,147 @@
+from typing import List, Optional, Tuple, Type
+
+import pytest
+from transformers import AutoTokenizer
+
+from vllm.multimodal.utils import rescale_image_size
+from vllm.sequence import SampleLogprobs
+
+from ..conftest import IMAGE_ASSETS, HfRunner, VllmRunner, _ImageAssets
+from .utils import check_logprobs_close
+
+pytestmark = pytest.mark.vlm
+
+HF_IMAGE_PROMPTS = IMAGE_ASSETS.prompts({
+    "stop_sign": "caption es",
+    "cherry_blossom": "What is in the picture?",
+    "boardwalk": "What is in the picture?",
+})
+
+IMAGE_TOKEN_ID = 257152
+
+models = ["google/paligemma-3b-mix-224"]
+
+
+def vllm_to_hf_output(vllm_output: Tuple[List[int], str,
+                                         Optional[SampleLogprobs]],
+                      model: str):
+    """Sanitize vllm output to be comparable with hf output."""
+    output_ids, output_str, out_logprobs = vllm_output
+
+    tokenizer = AutoTokenizer.from_pretrained(model)
+    eos_token_id = tokenizer.eos_token_id
+
+    hf_output_ids = [
+        token_id for idx, token_id in enumerate(output_ids)
+        if token_id != IMAGE_TOKEN_ID or output_ids[idx - 1] != IMAGE_TOKEN_ID
+    ]
+
+    hf_output_str = output_str
+
+    if hf_output_ids[-1] == eos_token_id:
+        hf_output_str = hf_output_str + tokenizer.decode(eos_token_id)
+
+    return hf_output_ids, hf_output_str, out_logprobs
+
+
+def run_test(
+    hf_runner: Type[HfRunner],
+    vllm_runner: Type[VllmRunner],
+    image_assets: _ImageAssets,
+    model: str,
+    *,
+    size_factors: List[float],
+    dtype: str,
+    max_tokens: int,
+    num_logprobs: int,
+    tensor_parallel_size: int,
+    distributed_executor_backend: Optional[str] = None,
+):
+    """Inference result should be the same between hf and vllm.
+
+    All the image fixtures for the test is under tests/images.
+    For huggingface runner, we provide the PIL images as input.
+    For vllm runner, we provide MultiModalDataDict objects 
+    and corresponding vision language config as input.
+    Note, the text input is also adjusted to abide by vllm contract.
+    The text output is sanitized to be able to compare with hf.
+    """
+    images = [asset.pil_image for asset in image_assets]
+
+    inputs_per_image = [(
+        [prompt for _ in size_factors],
+        [rescale_image_size(image, factor) for factor in size_factors],
+    ) for image, prompt in zip(images, HF_IMAGE_PROMPTS)]
+
+    # NOTE: take care of the order. run vLLM first, and then run HF.
+    # vLLM needs a fresh new process without cuda initialization.
+    # if we run HF first, the cuda initialization will be done and it
+    # will hurt multiprocessing backend with fork method (the default method).
+
+    # max_model_len should be greater than image_feature_size
+    with vllm_runner(model,
+                     dtype=dtype,
+                     tensor_parallel_size=tensor_parallel_size,
+                     distributed_executor_backend=distributed_executor_backend,
+                     enforce_eager=True) as vllm_model:
+        vllm_outputs_per_image = [
+            vllm_model.generate_greedy_logprobs(prompts,
+                                                max_tokens,
+                                                num_logprobs=num_logprobs,
+                                                images=images)
+            for prompts, images in inputs_per_image
+        ]
+
+    with hf_runner(model, dtype=dtype, is_vision_model=True) as hf_model:
+        hf_outputs_per_image = [
+            hf_model.generate_greedy_logprobs_limit(prompts,
+                                                    max_tokens,
+                                                    num_logprobs=num_logprobs,
+                                                    images=images)
+            for prompts, images in inputs_per_image
+        ]
+
+    for hf_outputs, vllm_outputs in zip(hf_outputs_per_image,
+                                        vllm_outputs_per_image):
+
+        check_logprobs_close(
+            outputs_0_lst=hf_outputs,
+            outputs_1_lst=[
+                vllm_to_hf_output(vllm_output, model)
+                for vllm_output in vllm_outputs
+            ],
+            name_0="hf",
+            name_1="vllm",
+        )
+
+
+@pytest.mark.parametrize("model", models)
+@pytest.mark.parametrize(
+    "size_factors",
+    [
+        # No image
+        [],
+        # Single-scale
+        [1.0],
+        # Single-scale, batched
+        [1.0, 1.0, 1.0],
+        # Multi-scale
+        [0.25, 0.5, 1.0],
+    ],
+)
+@pytest.mark.parametrize("dtype", ["float"])
+@pytest.mark.parametrize("max_tokens", [128])
+@pytest.mark.parametrize("num_logprobs", [5])
+def test_models(hf_runner, vllm_runner, image_assets, model, size_factors,
+                dtype: str, max_tokens: int, num_logprobs: int) -> None:
+    run_test(
+        hf_runner,
+        vllm_runner,
+        image_assets,
+        model,
+        size_factors=size_factors,
+        dtype=dtype,
+        max_tokens=max_tokens,
+        num_logprobs=num_logprobs,
+        tensor_parallel_size=1,
+    )

vllm/model_executor/models/__init__.py

@@ -49,6 +49,8 @@
     "OlmoForCausalLM": ("olmo", "OlmoForCausalLM"),
     "OPTForCausalLM": ("opt", "OPTForCausalLM"),
     "OrionForCausalLM": ("orion", "OrionForCausalLM"),
+    "PaliGemmaForConditionalGeneration":
+    ("paligemma", "PaliGemmaForConditionalGeneration"),
     "PhiForCausalLM": ("phi", "PhiForCausalLM"),
     "Phi3ForCausalLM": ("llama", "LlamaForCausalLM"),
     "Phi3VForCausalLM": ("phi3v", "Phi3VForCausalLM"),

vllm/model_executor/models/gemma.py

@@ -268,16 +268,22 @@ def __init__(
         normalizer = self.config.hidden_size**0.5
         self.register_buffer("normalizer", torch.tensor(normalizer))
 
+    def get_input_embeddings(self, input_ids: torch.Tensor) -> torch.Tensor:
+        return self.embed_tokens(input_ids)
+
     def forward(
         self,
         input_ids: torch.Tensor,
         positions: torch.Tensor,
         kv_caches: List[torch.Tensor],
         attn_metadata: AttentionMetadata,
+        inputs_embeds: Optional[torch.Tensor] = None,
     ) -> torch.Tensor:
-        hidden_states = self.embed_tokens(input_ids)
+        if inputs_embeds is not None:
+            hidden_states = inputs_embeds
+        else:
+            hidden_states = self.get_input_embeddings(input_ids)
         hidden_states *= self.normalizer
-
         residual = None
         for i in range(len(self.layers)):
             layer = self.layers[i]