57 Performance Testing Interview Questions (With Answers)

By Indeed Editorial Team

Published 9 June 2022

The Indeed Editorial Team comprises a diverse and talented team of writers, researchers and subject matter experts equipped with Indeed's data and insights to deliver useful tips to help guide your career journey.

Performance testing is an aspect of software quality assurance that determines how well a system executes its function. It's common for interviewers to ask a performance test engineer applicant questions relating to the field. Learning more about these types of questions can help you prepare for an upcoming interview. In this article, we discuss common performance testing questions and provide sample responses for your reference.

Related: What Does It Take To Be a Software Engineer?

General performance testing interview questions

Here are 19 examples of general performance testing interview questions to help you prepare for an interview:

  1. What are the main performance issues that performance testing can solve?

  2. What are some common problems users might experience with a software's performance?

  3. What are the main parameters of a performance test?

  4. Can you define and explain performance tuning?

  5. What's the significance of a long response time during a performance test?

  6. Can you explain the differences between the manual and automated methods of performance tests?

  7. Can you explain when soak testing is ideal and why?

  8. How would you approach conducting a performance test analysis?

  9. What types of monitors do you use during performance tests?

  10. What are some causes of decreased system performance?

  11. Can you explain manual correlation?

  12. Can you define automated correlation?

  13. What are some benefits of modular scripting methods?

  14. How do you conduct a content check during a performance test?

  15. Can you provide an example of a use case for a performance test?

  16. What are some elements of a physical test environment?

  17. How would you configure a network for performance testing?

  18. Can you define what a DNS protocol is?

  19. Can you define what protocol-based performance testing is and explain the benefits of such a test?

Background performance testing questions

Here are 13 background questions you might encounter during an interview:

  1. What performance testing tools do you have experience using?

  2. What's your experience with writing script for tests?

  3. Do you have any best practices for documenting test results?

  4. Do you have any experience with designing a performance test for an update on an app?

  5. Do you have any experience with volume testing?

  6. Can you describe a past experience where it was necessary to stop a performance test?

  7. Can you describe a scenario in your previous workplace where it was required to have repeated performance tests?

  8. Have you ever skipped a dry run test?

  9. Describe some of your experiences with user scenarios.

  10. Do you have any issues with desktop testing?

  11. Are you familiar with web testing?

  12. Illustrate your experience with end-to-end testing.

  13. What quality assurance practices do you use when testing software?

Related: How to Become a Software Tester: Overview, Duties and Salary

In-depth performance testing questions

Here are 20 in-depth performance testing interview questions you might encounter during an interview:

  1. How do you decide which tools to use for a specific performance test?

  2. What's the difference between spike testing and endurance testing?

  3. What are some human errors that occur in a performance test and what's your approach to preventing or resolving them?

  4. What metrics do you use when measuring a system's performance?

  5. Can you describe how you might design an automated performance test?

  6. What would you recommend to application developers if their site crashed with a low user load during a stress test?

  7. What kind of performance test would you use when preparing for a website's launch?

  8. Can you describe the process of application profiling?

  9. What would you do if a performance test's results are drastically different from the initial tolerance criteria?

  10. How do you collect data for a baseline performance test?

  11. Can you describe the different situations that require hardware tuning and software tuning?

  12. What are the performance test requirements for a mobile game app?

  13. Do you use any visual aids in a performance test report?

  14. How does performance testing correlate with performance engineering?

  15. How do you stop external variables from influencing a performance test?

  16. What tool would you use to simulate a high volume of user access requests at a given time?

  17. What are some signs of disk usage bottleneck?

  18. What is garbage collection's relation to performance testing?

  19. How do you assess if a CPU can handle a stress test?

  20. How do dynamic values work in a performance test?

Related: Software Developer vs. Software Tester: Salary and Skills

5 performance testing interview questions with sample answers

Here are five performance testing interview questions with sample answers:

1. Can you explain what performance testing is?

This is a basic performance testing question that interviewers might pose to candidates at the beginning of the interview. This question prompts the candidate to provide an overview of performance testing, while allowing the interviewer to assess their theoretical knowledge. Begin your answer by briefly defining performance testing, then explain how it relates to the position you're interviewing for.

Example: 'Performance testing finds out how well a device or an application maintains its responsiveness and stability during high-traffic conditions. A performance test typically involves giving the software a high workload and observing if the system can handle it without a decline in the quality of its service. Performance testing is conducted constantly and is an integral part of the website's testing cycle.'

Related: What Does a Performance Tester Do? Roles, Duties and Skills

2. What is a performance bottleneck and what is your approach to avoiding them?

A performance bottleneck is a common concept in website and software testing, and recruiters may ask about them to analyse your approach to addressing them. Begin by describing the various types of performance bottlenecks to convey your familiarity in this area, then you can provide your preferred strategy for resolving them. A well-explained answer can showcase your ability to provide solutions to common software issues to the interviewer.

Example: 'A performance bottleneck occurs when the data's processing rate doesn't meet the specified system requirements. I have experience in this area from my last employment, where we had an instance of memory bottlenecking as our website expanded. From that experience, I would say that the best prevention is to upgrade the physical servers. Making code adjustments to maximise the software can also be invaluable. Then, to prevent the bottlenecks from reoccurring, I would monitor our resources using APM tools.'

3. When conducting a benchmark performance test, what's your method for setting appropriate standards?

Determining test parameters is a prerequisite for conducting any performance tests. Hiring managers might ask this question to find out how much you know about popular testing methods in the industry and to learn about how you conduct different tests. It can be useful to illustrate your explanation with a hypothetical scenario to highlight your expertise and ensure that the interviewer understands you clearly.

Example: 'An efficient benchmark performance test involves using a practical standard when comparing test data. For example, I might collect real information about system usage, which can include information such as the average page loading time and the number of active users who are online at a given time.'

Related: 34 Manual Testing Interview Questions (With Example Answers)

4. Can you explain what a high throughput value means?

Interviewers can ask this question to assess your theoretical knowledge. In your answer, first define the term before explaining its relevance to the software testing process. Providing examples to illustrate its significance can highlight your understanding to the interviewer.

Example: 'A network throughput is the rate at which transactions or responses occur in a system. A high throughput value means that a system can process more data, resulting in increased performance. For example, during an initial test a website processes 250 hits per second. Following the update, there are 280 hits per second. This means that 30 more people can access the website simultaneously without a decline in performance.'

5. Can you explain the difference between functional and performance testing, and when to use each?

Recruiters can ask this question to find out if you're aware of the other steps of a software's testing cycle, like functional testing. Begin your answer by explaining the purpose of each test, followed by the application of the tests. Include unique characteristics of both methods in your response to highlight their differences.

Example: 'Functional testing establishes whether each feature in a software works according to the system requirements, while performance testing addresses how well a software performs tasks. Functional tests are typically performed by a single person, and used to explore a software's different features, look for errors and test user scenarios. Performance tests involve multiple professionals who use the software at once in an attempt to overwhelm the system. Both methods are essential to having a user-friendly final product.'

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