[Bugfix] Avoid repeatedly creating dummy data during engine startup

vllm/engine/llm_engine.py

@@ -409,6 +409,9 @@ def get_tokenizer_for_seq(sequence: Sequence) -> AnyTokenizer:
         # the next step without re-scheduling.
         self._skip_scheduling_next_step = False
 
+        # Don't keep the dummy data in memory
+        self.reset_mm_cache()
+
     def _initialize_kv_caches(self) -> None:
         """Initialize the KV cache in the worker(s).
 
@@ -913,6 +916,10 @@ def has_unfinished_requests_for_virtual_engine(
         """
         return self.scheduler[virtual_engine].has_unfinished_seqs()
 
+    def reset_mm_cache(self) -> bool:
+        """Reset the multi-modal cache."""
+        return self.input_preprocessor.mm_registry.reset_processor_cache()
+
     def reset_prefix_cache(self, device: Optional[Device] = None) -> bool:
         """Reset prefix cache for all devices."""
 

vllm/multimodal/processing.py

@@ -1026,6 +1026,11 @@ def put(
     def put_item(self, item: ProcessingCacheItem) -> None:
         self._cache[item.key] = item.value
 
+    def reset(self) -> bool:
+        self._cache.clear()
+
+        return True
+
 
 class BaseProcessingInfo:
     """Base class to provide the information necessary for data processing."""

vllm/multimodal/registry.py

@@ -88,6 +88,12 @@ def __init__(self) -> None:
 
         self._processing_cache = ProcessingCache(VLLM_MM_INPUT_CACHE_GIB)
 
+    def reset_processor_cache(self) -> bool:
+        """Reset the multi-modal processing cache."""
+        self._processing_cache.reset()
+
+        return True  # Success
+
     @deprecated("Legacy input processor/mapper pipeline has been removed. "
                 "Please update your model runner to use "
                 "`seq_group_metadata.multi_modal_data` directly without "
@@ -106,7 +112,7 @@ def get_max_tokens_per_item_by_modality(
         if not model_config.is_multimodal_model:
             return {}
 
-        processor = self.create_processor(model_config, disable_cache=True)
+        processor = self.create_processor(model_config, disable_cache=False)
         profiler = MultiModalProfiler(processor)
 
         seq_len = model_config.max_model_len
@@ -190,7 +196,7 @@ def get_mm_limits_per_prompt(
         if not model_config.is_multimodal_model:
             return {}
 
-        processor = self.create_processor(model_config, disable_cache=True)
+        processor = self.create_processor(model_config, disable_cache=False)
         profiler = MultiModalProfiler(processor)
         return profiler.get_mm_limits()
 
@@ -286,7 +292,7 @@ def get_decoder_dummy_data(
 
         The model is identified by ``model_config``.
         """
-        processor = self.create_processor(model_config, disable_cache=True)
+        processor = self.create_processor(model_config, disable_cache=False)
         profiler = MultiModalProfiler(processor)
         dummy_data = profiler.get_decoder_dummy_data(seq_len, mm_counts)
 
@@ -310,7 +316,7 @@ def get_encoder_dummy_data(
 
         The model is identified by ``model_config``.
         """
-        processor = self.create_processor(model_config, disable_cache=True)
+        processor = self.create_processor(model_config, disable_cache=False)
         profiler = MultiModalProfiler(processor)
         dummy_data = profiler.get_encoder_dummy_data(seq_len, mm_counts)
 

vllm/v1/engine/core.py

@@ -121,6 +121,9 @@ def __init__(self,
             self.batch_queue = queue.Queue(self.batch_queue_size)
         self.vllm_config = vllm_config
 
+        # Don't keep the dummy data in memory
+        self.reset_mm_cache()
+
     def _initialize_kv_caches(
             self, vllm_config: VllmConfig) -> tuple[int, int, KVCacheConfig]:
         start = time.time()
@@ -277,6 +280,15 @@ def shutdown(self):
     def profile(self, is_start: bool = True):
         self.model_executor.profile(is_start)
 
+    def reset_mm_cache(self):
+        # NOTE: Since this is mainly for debugging, we don't attempt to
+        # re-sync the internal caches (P0 processor, P0 mirror, P1 mirror)
+        if self.scheduler.get_num_unfinished_requests():
+            logger.warning("Resetting the multi-modal cache when requests are "
+                           "in progress may lead to desynced internal caches.")
+
+        self.mm_input_cache_server.reset()
+
     def reset_prefix_cache(self):
         self.scheduler.reset_prefix_cache()
 

vllm/v1/engine/core_client.py

@@ -88,6 +88,9 @@ def add_request(self, request: EngineCoreRequest) -> None:
     def profile(self, is_start: bool = True) -> None:
         raise NotImplementedError
 
+    def reset_mm_cache(self) -> None:
+        raise NotImplementedError
+
     def reset_prefix_cache(self) -> None:
         raise NotImplementedError
 
@@ -214,6 +217,9 @@ def shutdown(self) -> None:
     def profile(self, is_start: bool = True) -> None:
         self.engine_core.profile(is_start)
 
+    def reset_mm_cache(self) -> None:
+        self.engine_core.reset_mm_cache()
+
     def reset_prefix_cache(self) -> None:
         self.engine_core.reset_prefix_cache()
 
@@ -600,6 +606,9 @@ def abort_requests(self, request_ids: list[str]) -> None:
     def profile(self, is_start: bool = True) -> None:
         self.call_utility("profile", is_start)
 
+    def reset_mm_cache(self) -> None:
+        self.call_utility("reset_mm_cache")
+
     def reset_prefix_cache(self) -> None:
         self.call_utility("reset_prefix_cache")
 

vllm/v1/engine/llm_engine.py

@@ -240,6 +240,11 @@ def start_profile(self):
     def stop_profile(self):
         self.engine_core.profile(False)
 
+    def reset_mm_cache(self):
+        self.processor.mm_registry.reset_processor_cache()
+        self.processor.mm_input_cache_client.reset()
+        self.engine_core.reset_mm_cache()
+
     def reset_prefix_cache(self, device: Optional[Device] = None):
         self.engine_core.reset_prefix_cache()
 

vllm/v1/engine/mm_input_cache.py

@@ -83,3 +83,8 @@ def get_and_update_p1(
             full_mm_inputs.append(mm_input)
 
         return full_mm_inputs
+
+    def reset(self) -> bool:
+        self.mm_cache.clear()
+
+        return True

vllm/v1/engine/processor.py

@@ -54,6 +54,10 @@ def __init__(
         self.use_hash = self.mm_input_cache_client.use_cache or \
             self.cache_config.enable_prefix_caching
 
+    @property
+    def mm_registry(self):
+        return self.input_preprocessor.mm_registry
+
     def _validate_logprobs(
         self,
         params: SamplingParams,