Important Terminologies used in Performance Testing

Important Terminologies used in Performance Testing :

Non Functional requirements (NFRs) : NFRs are the business requirements cater to Security Testing, Resilience Testing, Compatibility Testing, Recovery Testing, Usability Testing, Localization Testing, Performance Testing, Scalability Testing.

Performance NFRs are defined in one or more parameters - Transaction response time (min/max/average/90th percentile), hits per second, throughput, transactions per second under desire load. One or more of these parameters are also known as Key Performance Indicators (KPIs).



NFRs are also known as Service Level Agreement (SLA)

For Example :

Expected maximum user load - 10,000 users

Target concurrency of 2500 users (SLA)

Response time threshold (KPI) of 15 seconds

Transaction : Transaction is an end-to-end measurement that defines the start and end point of a user request which is responded by a server. For Example – “Clicking a Submit Button”, “Clicking on web link”



Transaction Response Time: Time take by a transaction to get responded or serviced by the server.



Concurrency: The group of users within a business processing environment that are requesting same processing services (functionality) from the environment all at the same point in time.



Simultaneous Users: The group of users within a business processing environment that are requesting different processing services (functionalities) from the environment all at the same point in time.

Think Time: The time between the browser displaying a page to the user and the user clicking a link to browse to the next page. This time could be the time it takes the user to read the content of the page or decide what to do next. Load testing tool records this time when recording a Business Case and uses it to accurately simulate the users when performing a test




Virtual User: A software entity generated by the performance testing tool, that simulates a real user by repeatedly performing a Business Case during a load test



Throughput: Number of Request Completions Per Unit Time or

Number of response units (bytes/kilo bytes) received from server per unit of time (seconds/minutes/hour)
Examples of throughput in Performance Testing:


Number of banking transactions per minute

Number of orders per minute

Number of web interactions per second

Number of disk I/Os per second, bandwidth


Case Study on Throughput:

At ABC Bank there are


2 million withdrawals per day,

2 million inquiries per day, and

1 million deposits per day.

75% of the transactions occur in a 3 hour window –11am to 2pm.

What is the peak throughput?

Solution :



Daily throughput = 2+2+1 = 5 million transactions/day Peak throughput = 75% of (5 million transactions per 3 hours)

= 0.75 x 5 million / 3 = 1.25 million / hour