diff --git a/src/memos/api/product_api.py b/src/memos/api/product_api.py
index 681644a0..709ad74f 100644
--- a/src/memos/api/product_api.py
+++ b/src/memos/api/product_api.py
@@ -33,6 +33,6 @@
 
     parser = argparse.ArgumentParser()
     parser.add_argument("--port", type=int, default=8001)
-    parser.add_argument("--workers", type=int, default=32)
+    parser.add_argument("--workers", type=int, default=1)
     args = parser.parse_args()
     uvicorn.run("memos.api.product_api:app", host="0.0.0.0", port=args.port, workers=args.workers)
diff --git a/src/memos/llms/openai.py b/src/memos/llms/openai.py
index 698bc326..47818a94 100644
--- a/src/memos/llms/openai.py
+++ b/src/memos/llms/openai.py
@@ -11,6 +11,7 @@
 from memos.llms.utils import remove_thinking_tags
 from memos.log import get_logger
 from memos.types import MessageList
+from memos.utils import timed
 
 
 logger = get_logger(__name__)
@@ -56,6 +57,7 @@ def clear_cache(cls):
         cls._instances.clear()
         logger.info("OpenAI LLM instance cache cleared")
 
+    @timed
     def generate(self, messages: MessageList) -> str:
         """Generate a response from OpenAI LLM."""
         response = self.client.chat.completions.create(
@@ -73,6 +75,7 @@ def generate(self, messages: MessageList) -> str:
         else:
             return response_content
 
+    @timed
     def generate_stream(self, messages: MessageList, **kwargs) -> Generator[str, None, None]:
         """Stream response from OpenAI LLM with optional reasoning support."""
         response = self.client.chat.completions.create(
diff --git a/src/memos/llms/qwen.py b/src/memos/llms/qwen.py
index a47fcdf3..b2d662ff 100644
--- a/src/memos/llms/qwen.py
+++ b/src/memos/llms/qwen.py
@@ -5,6 +5,7 @@
 from memos.llms.utils import remove_thinking_tags
 from memos.log import get_logger
 from memos.types import MessageList
+from memos.utils import timed
 
 
 logger = get_logger(__name__)
@@ -16,6 +17,7 @@ class QwenLLM(OpenAILLM):
     def __init__(self, config: QwenLLMConfig):
         super().__init__(config)
 
+    @timed
     def generate(self, messages: MessageList) -> str:
         """Generate a response from Qwen LLM."""
         response = self.client.chat.completions.create(
@@ -33,6 +35,7 @@ def generate(self, messages: MessageList) -> str:
         else:
             return response_content
 
+    @timed
     def generate_stream(self, messages: MessageList, **kwargs) -> Generator[str, None, None]:
         """Stream response from Qwen LLM."""
         response = self.client.chat.completions.create(
diff --git a/src/memos/mem_os/product.py b/src/memos/mem_os/product.py
index a4ab4ef2..d6464389 100644
--- a/src/memos/mem_os/product.py
+++ b/src/memos/mem_os/product.py
@@ -179,14 +179,14 @@ def _restore_user_instances(
         """
         try:
             # Get all user configurations from persistent storage
-            user_configs = self.user_manager.list_user_configs()
+            user_configs = self.user_manager.list_user_configs(self.max_user_instances)
 
             # Get the raw database records for sorting by updated_at
             session = self.user_manager._get_session()
             try:
                 from memos.mem_user.persistent_user_manager import UserConfig
 
-                db_configs = session.query(UserConfig).all()
+                db_configs = session.query(UserConfig).limit(self.max_user_instances).all()
                 # Create a mapping of user_id to updated_at timestamp
                 updated_at_map = {config.user_id: config.updated_at for config in db_configs}
 
diff --git a/src/memos/mem_user/mysql_persistent_user_manager.py b/src/memos/mem_user/mysql_persistent_user_manager.py
index f8983c87..99e49d20 100644
--- a/src/memos/mem_user/mysql_persistent_user_manager.py
+++ b/src/memos/mem_user/mysql_persistent_user_manager.py
@@ -188,7 +188,7 @@ def delete_user_config(self, user_id: str) -> bool:
         finally:
             session.close()
 
-    def list_user_configs(self) -> dict[str, MOSConfig]:
+    def list_user_configs(self, limit: int = 1) -> dict[str, MOSConfig]:
         """List all user configurations.
 
         Returns:
@@ -196,7 +196,7 @@ def list_user_configs(self) -> dict[str, MOSConfig]:
         """
         session = self._get_session()
         try:
-            user_configs = session.query(UserConfig).all()
+            user_configs = session.query(UserConfig).limit(limit).all()
             result = {}
 
             for user_config in user_configs: