What is Performance Testing?

Purpose:

• To demonstrate that the systems meets performance criteria.
• To compare two systems to find which performs better.
• To measure what parts of the system or workload cause the system to perform badly
  

Performance of a system is generally measured in terms of response time for the user activity. To illustrate, a customer likes to withdraw money from an Automated Teller Machine (ATM) counter of a specific bank. Customer inserts debit/credit card and waits for the response. If the system takes more than 5 minutes (say) to deliver the cash, customer may not appreciate the system. In this situation, though, the system is
functioning (delivering cash) according to requirements. It fails in terms of performance (takes more than 5 minutes to complete the transaction).