[Bugfix] Clear P0 mm sender cache on sleep/pause to fix mm_hash desync

tests/multimodal/test_cache.py

@@ -549,3 +549,42 @@ def test_processor_cache_shared_across_loras():
 
     receiver_cache.get_and_update_features([feature_lora_b])
     assert feature_lora_b.data == item_data
+
+
+_SLEEP_VISION_PROMPT = (
+    "<|im_start|>system\nYou are a helpful assistant.<|im_end|>"
+    "\n<|im_start|>user\n<|vision_start|><|image_pad|><|vision_end|>"
+    "What is in the image?<|im_end|>\n"
+    "<|im_start|>assistant\n"
+)
+
+
+@pytest.mark.skipif(
+    not torch.cuda.is_available(),
+    reason="sleep mode regression requires a CUDA GPU",
+)
+def test_sleep_wake_preserves_mm_cache_consistency():
+    """Regression for vllm-project/vllm#42995."""
+    from vllm import LLM, SamplingParams
+    from vllm.assets.image import ImageAsset
+
+    image = ImageAsset("stop_sign").pil_image
+    prompt = {
+        "prompt": _SLEEP_VISION_PROMPT,
+        "multi_modal_data": {"image": image},
+    }
+    sampling_params = SamplingParams(temperature=0, max_tokens=8)
+
+    llm = LLM(
+        model="Qwen/Qwen2-VL-2B-Instruct",
+        enable_sleep_mode=True,
+        enforce_eager=True,
+        gpu_memory_utilization=0.5,
+        max_model_len=2048,
+    )
+
+    llm.generate([prompt], sampling_params)
+    llm.sleep(level=1)
+    llm.wake_up()
+    output2 = llm.generate([prompt], sampling_params)
+    assert output2[0].outputs[0].text

vllm/v1/engine/async_llm.py

@@ -781,6 +781,8 @@ async def pause_generation(
                 stacklevel=2,
             )
             mode = "wait"
+        if clear_cache:
+            await self.renderer.clear_mm_cache_async()
         await self.engine_core.pause_scheduler_async(mode=mode, clear_cache=clear_cache)
         # Small sleep to help ensure that final outputs from any in-flight requests are
         # returned prior to this method returning. These outputs come out of the engine
@@ -927,6 +929,8 @@ async def reset_encoder_cache(self) -> None:
         await self.engine_core.reset_encoder_cache_async()
 
     async def sleep(self, level: int = 1, mode: PauseMode = "abort") -> None:
+        if level >= 1:
+            await self.renderer.clear_mm_cache_async()
         await self.engine_core.sleep_async(level, mode)
 
         if self.logger_manager is not None:

vllm/v1/engine/llm_engine.py

@@ -350,6 +350,8 @@ def reset_encoder_cache(self) -> None:
         self.engine_core.reset_encoder_cache()
 
     def sleep(self, level: int = 1, mode: PauseMode = "abort"):
+        if level >= 1:
+            self.renderer.clear_mm_cache()
         self.engine_core.sleep(level, mode)
 
         if self.logger_manager is not None: