Cloudsim is not an application-level simulator (response time, security, etc. are application-level metrics). This simulator addresses only infrastructure layer (VM, Hardware, etc). But, you can treat each cloudlet as an user request, because each cloudlet has a time completion. Based on that, you can interpret this time as the response time.
Use the cloudlet to send the request as per (UB)userbase to DC(datacenter) and calculate the response time and throughput by using the formulas. Time calculation may be ms to hr. Its depend on load and availability. Also use cloudsim with cloud analysis tool