Avoid compiling entity service schema when passed defaults (#112099)

* Avoid compiling entity service schema when passed defaults

* dry

homeassistant/helpers/config_validation.py

@@ -1235,9 +1235,7 @@ TARGET_SERVICE_FIELDS = {
 }
 
 
-def make_entity_service_schema(
+def _make_entity_service_schema(schema: dict, extra: int) -> vol.Schema:
-    schema: dict, *, extra: int = vol.PREVENT_EXTRA
-) -> vol.Schema:
     """Create an entity service schema."""
     return vol.Schema(
         vol.All(
@@ -1255,6 +1253,21 @@ def make_entity_service_schema(
     )
 
 
+BASE_ENTITY_SCHEMA = _make_entity_service_schema({}, vol.PREVENT_EXTRA)
+
+
+def make_entity_service_schema(
+    schema: dict, *, extra: int = vol.PREVENT_EXTRA
+) -> vol.Schema:
+    """Create an entity service schema."""
+    if not schema and extra == vol.PREVENT_EXTRA:
+        # If the schema is empty and we don't allow extra keys, we can return
+        # the base schema and avoid compiling a new schema which is the case
+        # for ~50% of services.
+        return BASE_ENTITY_SCHEMA
+    return _make_entity_service_schema(schema, extra)
+
+
 SCRIPT_CONVERSATION_RESPONSE_SCHEMA = vol.Any(template, None)