[Hotfix][Core][VLM] Disable chunked prefill by default and prefix caching for multimodal models (#8425)

vllm/engine/arg_utils.py

@@ -843,6 +843,13 @@ class EngineArgs:
         device_config = DeviceConfig(device=self.device)
         model_config = self.create_model_config()
 
+        if model_config.is_multimodal_model:
+            if self.enable_prefix_caching:
+                logger.warning(
+                    "--enable-prefix-caching is currently not "
+                    "supported for multimodal models and has been disabled.")
+            self.enable_prefix_caching = False
+
         cache_config = CacheConfig(
             block_size=self.block_size if self.device != "neuron" else
             self.max_model_len,  # neuron needs block_size = max_model_len
@@ -874,7 +881,10 @@ class EngineArgs:
             # If not explicitly set, enable chunked prefill by default for
             # long context (> 32K) models. This is to avoid OOM errors in the
             # initial memory profiling phase.
-            if use_long_context:
+
+            # Chunked prefill is currently disabled for multimodal models by
+            # default.
+            if use_long_context and not model_config.is_multimodal_model:
                 is_gpu = device_config.device_type == "cuda"
                 use_sliding_window = (model_config.get_sliding_window()
                                       is not None)