Performance Testing: An Overview of its Importance, Metrics, and Examples

The performance of your software is important for its success. Project managers, developers, and marketers measure the performance using testing tools to know how an app is performing when live.

Performance testing has its own set of challenges. For instance, changes in application behavior in scaled-down environments. However, we must first understand why performance testing is necessary in the first place.

To name a few things, we’ll talk about:

  • Why performance testing is needed
  • Types of performance testing
  • What does performance testing measure
  • Performance testing success measure
  • Performance testing process
  • Performance testing example

Why is performance testing needed?

Following are some of the reasons:

1. Mobile app errors are now much higher than ever. Mobile applications face network issues, especially when the server is overloaded. It becomes even more difficult if the applications are running on unreliable mobile networks. Some of the issues that apps face in such a situation are as follows:

  • Problems downloading images or images that are broken.
  • Massive gaps in the content feed.
  • Errors in booking or checkout.
  • Timeouts are used frequently.
  • Freezing and stalling.
  • Uploads that failed.

2. Poor application experience means frustrated customers, which leads to lost revenues. Research shows that over 47 percent of the respondents would exit the application when faced with a broken image, and switch to a different platform.

3. Application speed changes as per region. It is critical to ensure that users of the application all over the world can use it easily and without experiencing any network issues.

4. Moreover, a system may run smoothly with only 1,000 concurrent users, but it might behave randomly if the user base increases to 10,000. Performing performance tests on a system determines whether or not it is stable, scalable, and fast enough to handle high demand.

While there are different tools to test the above criteria, there are different processes that determine if the system works per the established reference point. It is also important to plan how performance tests should be performed.

Types of Performance Testing

Spike testing

A technique known as spike testing examines how quickly the software responds to sudden, large increases in the amount of load generated by the system.

Load testing

An application’s ability to handle anticipated user loads is tested during a load test. The goal is to identify performance bottlenecks before a software application goes live.

Scalability testing

Testing for scalability – Determines the application’s ability to “scale up” in response to an increase in user load. It aids in the planning of software capacity expansions.

Stress testing

Stress testing entails putting an application through its paces under extreme workloads to see how it reacts to spikes in traffic or processing demands. The objective is to identify applications that are just about to be submitted.

Endurance testing

Ensures your software can handle the expected load for a long period of time through endurance testing.

Volume testing

Data is populated into a database during volume testing, so the overall behaviour of the software system is monitored. The goal is to see how well a software application performs with varying database sizes.

What does performance testing measure?

Response times and possible errors are among the things that performance testing looks at. In this way, you’ll be able to confidently identify performance bottlenecks, bugs and mistakes – and choose a way to optimize your application for the problem (s). Tests of performance have shown that speed, response time, load time, and scalability are the most common problems. 

Excessive Load Times

To start an application, you’ll need a certain amount of load time. Delays should be kept to a minimum to provide the best possible user experience.

Poor Response Times

Latency is what elapses between a user entering information into an application and the response to its action. Long response times significantly reduce the interest of users within the application.

Limited Scalability

Limited scalability is a problem with an application’s ability to scale up or scale down as needed to accommodate more or fewer users. While the appliance works well with a small number of users, it starts to struggle as the number of users grows.


Bottlenecks are performance-degrading impediments in a software system. They’re usually the result of faulty hardware or bad code.

Performance Testing Success Metrics

The critical metrics in your tests must be clearly defined before you begin testing. These parameters generally include:

  • Hits per second – the number of hits on an online server during each second of a load test.
  • Hit ratios – cached data instead of expensive I/O operations handles the number of SQL statements. If you’re serious about solving the bottleneck problem, you should start here.
  • Amount of connection pooling – the number of user requests met by pooled connections. The more requests met by connections within the pool, the higher the performance is going to be.
  • Maximum active sessions – the utmost number of sessions that may move directly.
  • Disk queue length – When a sample interval occurs, the average number of ‘read and write’ requests that go into the disc queue during that time are recorded.
  • Network output queue length – Length of the network output queue in packets (instead of bytes). Anything less than two indicates the presence of a delay or bottlenecking, which must be addressed immediately.
  • Network bytes total per second – Bytes sent and received on the network interface, including framing characters, are measured in network bytes per second.
  • Response time – the amount of time it takes for a user to enter a letter of invitation and receive the first character of the response.
  • Throughput – The rate at which a computer or network receives requests per second is known as throughput.

Performance Testing Process

Performance testing methodology varies widely, but the goal remains the same regardless of the methodology used. With the help of this, you can demonstrate that your software system meets certain performance criteria. It’s used to see how well two software systems compare to one another. It can also help you find performance bottlenecks in your software system.

Here is the performance testing procedure. 

  • Recognize your testing environment – Understand your physical test environment, production environment, and testing tools. Before you begin testing, learn about the hardware, software, and network configurations that will be used. It will assist testers in creating more efficient tests. It will also aid in identifying potential issues that testers may face during the performance testing. 
  • Determine the performance acceptance criteria – This includes the throughput targets and constraints, response times and resource allocation. In addition to these objectives and limitations, defining project success criteria is also necessary. Testing should be empowered to set performance criteria and goals because project specifications may not always include a diverse set of performance benchmarks. Sometimes there may be none at all. Whenever possible, find a comparable application and use that to set performance goals.
  • Plan and design performance tests –Determine how end-user usage differs and identify key scenarios to test for them. A wide range of end users must be simulated, performance test data planned and metrics outlined.
  • Setting up the test environment – Before starting the test, make sure your testing environment is ready. Organize tools and other resources as well.
  • Implement test design – Create performance tests in accordance with your test plan.
  • Run the tests – Put the code into action and monitor the results.
  • Analyze, fine-tune, and retest – Compile, analyze, and disseminate the results of the tests. Then make any necessary adjustments and retest to see if the system’s performance has improved or deteriorated.

Example Performance Test Cases

  • When 1000 users access the website at the same time, the response time is no longer than 4 seconds.
  • When network connectivity is slow, ensure that the response time of the Application Under Load is within an acceptable range.
  • Examine the maximum number of users that the application can support before crashing.
  • Analyze the database execution time when 500 records are read and written simultaneously.
  • Make sure to keep an eye on CPU and memory usage, especially when the system is under heavy load.
  • Test the application’s response time under various load conditions, including light, normal, moderate, and heavy.

During the execution of the performance test, vague terms such as acceptable range, heavy load, and so on are replaced by concrete numbers. These numbers are determined by performance engineers based on business requirements and the technical landscape of the application.


Software engineers must conduct performance testing on all new products before releasing them to the market. There is no risk of a product failure, so customer satisfaction is guaranteed. Gaining a competitive advantage usually outweighs the costs of conducting performance testing.

About Galaxy Weblinks

We specialize in delivering end-to-end software design & development services and have hands-on experience with automation testing in agile development environments. Our engineers, QA analysts, and developers help improve security, reliability, and features to make sure your business application and IT structure scale and remain secure.


Stay up to date with latest happenings in our space