Performance Testing


Performance Testing is the testing to check the speed, scalability, and stability of the software application under different levels of workload. In other words, performance testing ensures that the software product will give expected speed, scalability, and stability when under the expected workload.

Verifying the product for its functionality and features through unit, integration and system testings is not enough if the product is slow or unstable. Hence, the performance testing targets to find the performance blockages of the product for their rectification.

You can read about System Testing which we have covered in previous topics.

Definition of Performance Testing

The performance testing is the non-functional testing to measure the performance of the product in terms of its responsiveness and stability under various loads. The objective of performance testing is to identify the conditions under which the performance of the application is below the expectations.

These test cases target to find out if the software meets the expected requirements for application’s response time, scalability and stability. Performance testing is also called Perf Testing.

Performance Testing Parameters

  • Responsiveness: It measures the response time of the product at various load levels.
  • Scalability: This is the ability of the system to scale up or down the number of user requests it caters to.
  • Stability: It verifies if the system is stable under different load levels.
  • Reliability: It verifies if the behavior or the response of the system is as per the expectations under different load levels.

Why do Performance Testing

  • Verifying just the functionality is not sufficient to ensure the quality of the product. Not only the product should have the right functionality but it should also give optimum speed and performance.
  • This testing uncovers the areas of the product which can give better performance.
  • Performance testing helps with increasing confidence of the stakeholders into the product that it can work optimally during heavy workloads under expected limits.
  • Good performance products definitely have better sales and good market hold than those with performance issues.
  • There are several mission-critical applications like airlines, investment banking, and medical which have very stringent performance criteria thereby making performance testing a very crucial one.

Performance Issues 

The performance problems to look for are like a slow running system, a system which takes more time to load and the one which hangs up at a particular function. Any of these issues can degrade the quality of the product and thereby the sales to a large extent.

  • Slow Speed: At times, the product works at a very slow speed like takes long to load the web pages or to show the response. Such a slow responding system is sure to lose its users.
  • Load time: Application takes a long time to become up and running. Although every application needs some loading time if the application takes more than the usual time then it needs to be evaluated.
  • Low scalability: If the product does not give optimum performance when the number of user requests increases, there is an issue with the scalability of the product.

Reasons for Performance Issues

There are several causes of performance issues like

  • The design flow of the system is making it slow
  • There can be certain blockages due to faulty code blocks which cause the product to hang during some period of workloads. These are also called bottlenecks.
  • There can be some environmental issues like networks, servers or hardware problems.
  • Poor utilization of resources like CPU utilization, slow operating systems, or database connections can cause slow response times.

Types of Performance Testing

Performance has several facets. Hence, there are many types of performance testing each focusing on a particular area of performance parameters. Some of them are below:

  • Stress testing: In this testing, testers subject the application to extreme workloads to check its behavior under that and to find the breaking point of the application. This testing determines the maximum load the system can withstand.
  • Load testing: This testing subjects the application to a range of expected workloads and then measures its performance parameters.
  • Scalability testing – This testing establishes scalability of the system by increasing or decreasing the user loads. Therefore, it tests if the system is capable to function when user requests increase or decrease in number.
  • Endurance testing: As the name suggests it measures the applications ability to run with the expected load over a long durations.
  • Spike testing: It verifies that the software responds appropriately during spikes of workloads.
  • Volume testing: This testing focusses on the processing of a large volume of data. In this testing, testers load a large amount of data in the database in an incremental manner. Then the application runs with this huge database to measure its performance.
  • Reliability Testing: It verifies if the system is able to recover to its normal state after a failure or breakdown. It also measures the time the system takes to recover.

Performance testing process

Requirement Analysis

The first step towards performance testing is to analyze the product for its performance requirements benchmarks. What are the expectations of the stakeholders in terms of the speed, scalability, and stability of the product? It is a crucial step which provides definite goals towards future steps of performance testing.

Devise Performance Test approach

Now that the goals are clear, the next step is how to achieve them. For that working out a test strategy is important. In the test strategy, we determine what is the scope of current performance testing phase. It also establishes what type of testing is required to fulfill the objectives and details of testing resources. The testing team comes up with the type and sequence of performance testings they are going to perform. Also, they select the tools they are going to use. Next, they evaluate the test environment which they will use.

Develop test plan

After finalizing the test approach, the next step is to come up with a detailed test plan. The test plan is the document which guides the entire testing process. It enlists and analyzes in detail the testing schedule, test tools, and environment. It provides details of all the test scenarios of the testing and includes developments of test cases.

Setup Test environment

After finalizing the tool, the test environment needs to set up. It totally depends on the product, hardware, network, and testing tool. A suitable test environment using which proper workloads can be effectively provided to the product is set up.


Test cases steps are executed and test results are recorded. The actual test results are compared with the expected results. Based on the comparison, pass and fail is registered. The identified bugs are recorded in the bug reporting tool for the fixing.

Test results analysis 

The analysis of test results happens after the completion of the execution phase. Total test cases passed and failed are evaluated. Testers prepare test reports with the details of the number of test cases covered and the test cases which are remaining. It shows the pass and the fail percentage. Testers present test results to all the stakeholders.

Test Closure

The test process is closed after evaluation of exit criteria. The exit criteria impose the percentage of test case execution and pass percentage, retest percentage. After the criteria are fulfilled, the performance testing phase is closed.

Performance Testing Tools

Performance testing is very much tool based. There are wide spectra of tools available in the market to help setup performance test cases. Some of the commonly used ones are:-

  • Load Runner: It is a licensed tool from HP which is a market leader in the area of performance testing. This tool helps to increase the number of user loads to many thousands thereby evaluating the system’s performance. It simulates the real user experience.
  • Jmeter: Apache JMeter is an open source tool which helps with load testing of web applications. Using this tool, the application can be sent a large number of requests for performance evaluation.
  • WebLoad: It is a load and performance testing tool for web applications. It helps to perform load and stress testing on internet-based applications by generating load from the on-premises machines as well as the cloud.
  • LoadNinja: Smartbear LoadNinja helps to create complex load tests. It can replace load emulators with real browsers.  Also, it works at a fast speed getting fast results.
  • SmartMeter: It is a load and performance testing tool with new age utilities. It provides an embedded browser. In this tool, testers can create test cases without scripting. Thus, it is very easy to learn and implement.


It is of utmost importance to test the system for its performance parameters. Without performance testing, a system is vulnerable to slowness, breakdown or bottlenecks during its work. No user enjoys working on a slow responding system. Similarly, the system which breaks in heavy loads can push its users away. Hence, performance testing should be part of the overall test strategy of the project to ensure a successful product.


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