34 Performance Testing Interview Questions (With Answers)

Updated 12 September 2023

Performance testing or perf testing helps determine the responsiveness and stability of an application or software under real-world workloads. A performance test simulates various possible user scenarios and understands the behaviour of the applications in a variety of situations. Learning commonly asked interview questions can help you prepare and increase your chances of getting hired. In this article, we list various performance testing interview questions and go through some sample answers to help you during your interview.

General Performance Testing Interview Questions

Knowing the answer to performance testing interview questions can help you gain a competitive advantage over other candidates. Having a working knowledge of perf testing and familiarity with industry benchmarks gives hiring managers a better sense of your ability to produce high-quality and functional applications. Performance testing ensures software quality and helps evaluate application output, data transfer speed, command response times, network bandwidth usage, processing speed, memory utilisation and workload efficiency.

It is important to be familiar with performance testing tools, operating systems and trends, scripting skills, expertise using monitoring tools and strong analytic and problem-solving skills to increase your chances of getting hired. Following are some general performance testing interview questions you can expect:

Tell me about yourself.
Why did you leave your last job?
What are your greatest strengths?
What are your weaknesses?
Where do you see yourself in five years?
What excites you about software testing?
What would your supervisor say about you?
How can you contribute to this company?
What are your biggest accomplishments?

Questions About Experience And Background

As part of the testing program, these professionals design test parameters, troubleshoot errors and create final testing procedures. Hiring managers often ask questions about your experience, which includes your educational qualifications and professional background. Here are some questions you can expect:

Do you think there is a difference between hard work and smart work?
What experience do you have for this position?
Describe your related experience.
How did your past work experience prepare you for the job?
How do you handle pressure or stressful situations?
Do you prefer working independently or as a team?
What are your hobbies outside of work?
What are your salary expectations?
What additional training did you take to improve yourself?
What did you like the most about your previous job?
Can you briefly talk about your previous projects?

In-Depth Questions

In-depth questions aim at your expertise in using different perf testing tools, hands-on experience with programming languages and an understanding of different systems environments. Here are some examples of such questions that you may encounter:

Outline the types of performance testing.
What are some parameters for performance testing?
What is the difference between performance testing and functional testing?
What is the method for collecting data for a baseline performance test?
Outline the major tools for performance testing.
What is desktop testing?
Differentiate between performance testing and performance engineering.
Differentiate between endurance testing and spike testing.

6 Performance Testing Interview Questions With Sample Answers

The ability to discuss performance testing during an interview demonstrates your competence in a software testing or development position. Here are some interview questions and their sample answers:

1. What are the criteria for entering and exiting performance testing?

A hiring manager expects candidates to know about entry criteria, which are specific conditions that developers and testers ensure before a performance test and exit criteria, which involve fixing errors and maintaining reports. Knowledge of the entry and exit criteria can help describe the issue, identify factors related to the software problems and find ways to correct them through perf testing.

Example answer: "It is only at the design level that one can initiate performance testing. The entry criteria depend on the defining objectives before testing, the selection of performance test type, availability of a dedicated setup and testing environment and the restoration of the program's database. After the testing is complete, we collect and analyse the results for improvements. The entire life cycle of software development involves performance tuning based on factors such as tolerance criteria of stress and performance, scalability and reliability under load and application release time." Related: What Does A Performance Tester Do? (Salary And Skills)

2. What are performance bottlenecks and how do you avoid them?

Testing software and websites often encounter bottlenecks, so interviewers might ask you about how to overcome them during testing. Explain the types of performance bottlenecks and then a basic prevention strategy to demonstrate your expertise in computer systems.

Example answer: "Performance bottlenecking occurs when one component of a computer system slows down the entire system. As our website grew, we ran into CPU and memory bottlenecks, which required us to upgrade our physical servers. Using APM tools, I began monitoring our resource usage to prevent bottlenecks."

3. What does a high throughput value mean?

One of the key metrics in perf testing is throughput. It determines the rate at which software can process requests during a particular timeframe. Describe how the term relates to software testing and provide examples to demonstrate its relevance.

Example answer: "The throughput of a system is the maximum number of data transactions or server responses it can process in a given period. Higher throughput means that a server can process more information, perform better and serve more users. If a website can process 150 hits per second and 50 hits per second after an update, it means 50 more people can access it at the same time without having to wait."

4. Why do you want to work for our company?

It is important to research the company and learn about its background, vision, goals, work culture, products or services and recent news. You can answer this question by showing your understanding and interest in working for the organisation. You can also explain how this position fits into your career plans and what you can offer the organisation.

Example answer: Having worked as an automation tester for two years, I look forward to joining your company as a performance tester. My colleagues in my professional network often talk about how great AK Enterprises is in providing a full suite of QA testing services and providing new opportunities and extensive training programmes to help employees. I have a sound record of working collaboratively with a variety of performance testing tools and designing effective tests.

I am excited to bring my knowledge of scripting languages and cloud services to a noble organisation such as yours and work together to provide high quality and innovative services for performance testing."

5. What is the difference between benchmark testing and baseline testing?

Hiring managers expect you to have a strong understanding of non-functional testing to ensure you can develop software applications that satisfy business requirements and performance standards. While benchmark testing and baseline testing are similar, there are several differences between the two.

Example answer: "Benchmark testing is the process of testing software against certified market standards. This refers to testing the software for performance and comparing it to the requirements set by standards organisations and other regulatory bodies. It ensures that the software meets and exceeds all certified regulatory requirements.

A baseline test compares the software's performance against a previous benchmark. Upon the completion of the first test, we conduct the second test, where we compare the most recent test to the results from the previous test to gauge the level of progress achieved."

6. What are some of the common problems faced by users?

A functional computer or server can slow down due to performance issues. Interviewers look for candidates who are aware of such issues and can address them to identify the underperforming components to bring the system to operable conditions. Here is how you can respond:

Example answer: "Some common problems faced by users include longer loading time, poor scalability, poor response time and bottlenecks such as hardware issues and coding errors."