Overhead of a placeholder irule?

I have a site that I need to deploy where it is not yet clear whether or not I will need to use an iRule. I tested an iRule that is just a placeholder. (That basically just contains a pool statement). There is no noticeable difference in response time.

 

 

Is there *ANY* additional overhead to using this irule vs setting a default pool for the VIP? (I understand that this would not make a difference for a low traffic site).

 

 

Thanks,

 

Brian