Speed up single entity/response service calls (#96729)

* Significantly speed up single entity/response service calls

Since the majority of service calls are single entity, we can
avoid creating tasks in this case. Since the multi-entity
service calls always check the result and raise, we can switch
the asyncio.wait to asyncio.gather

* Significantly speed up single entity/response service calls

Since the majority of service calls are single entity, we can
avoid creating tasks in this case. Since the multi-entity
service calls always check the result and raise, we can switch
the asyncio.wait to asyncio.gather

* revert

* cannot be inside pytest.raises

* one more

* Update homeassistant/helpers/service.py

homeassistant/helpers/service.py

@@ -741,6 +741,8 @@ async def entity_service_call(  # noqa: C901
     Calls all platforms simultaneously.
     """
     entity_perms: None | (Callable[[str, str], bool]) = None
+    return_response = call.return_response
+
     if call.context.user_id:
         user = await hass.auth.async_get_user(call.context.user_id)
         if user is None:
@@ -851,13 +853,27 @@ async def entity_service_call(  # noqa: C901
         entities.append(entity)
 
     if not entities:
-        if call.return_response:
+        if return_response:
             raise HomeAssistantError(
                 "Service call requested response data but did not match any entities"
             )
         return None
 
-    if call.return_response and len(entities) != 1:
+    if len(entities) == 1:
+        # Single entity case avoids creating tasks and allows returning
+        # ServiceResponse
+        entity = entities[0]
+        response_data = await _handle_entity_call(
+            hass, entity, func, data, call.context
+        )
+        if entity.should_poll:
+            # Context expires if the turn on commands took a long time.
+            # Set context again so it's there when we update
+            entity.async_set_context(call.context)
+            await entity.async_update_ha_state(True)
+        return response_data if return_response else None
+
+    if return_response:
         raise HomeAssistantError(
             "Service call requested response data but matched more than one entity"
         )
@@ -874,9 +890,8 @@ async def entity_service_call(  # noqa: C901
     )
     assert not pending
 
-    response_data: ServiceResponse | None
     for task in done:
-        response_data = task.result()  # pop exception if have
+        task.result()  # pop exception if have
 
     tasks: list[asyncio.Task[None]] = []
 
@@ -895,7 +910,7 @@ async def entity_service_call(  # noqa: C901
         for future in done:
             future.result()  # pop exception if have
 
-    return response_data if call.return_response else None
+    return None
 
 
 async def _handle_entity_call(