The first rule of control engineering is:
If you cannot measure it, you cannot control it .
When you set your performance objectives, take a practical look at what you can measure. While you may want to establish a high-level throughput objective of, say, "55 transactions per second" there may not be an easy way to measure this. Instead, consider using an indicator that is readily available. For example, the BEGINLUW counter records how may logical units of work (LUWs) started during the last monitoring period. While this does not actually represent the number of transactions per second, it does act as a rough indicator of throughput.