Software Performance Testing: A Complete Overview

Timothy Joseph
Timothy Joseph | January 10, 2023

Software Performance Testing: A Complete Overview

Imagine that you have just created an extension app that runs in the background. Confident in its functionality after beta testing, you decide to release it for public use. A few months later, you start receiving complaints about how your extension app slows down other computer applications. Was there a problem with the extension app? No. But when it comes to overall performance, there’s clearly much to be desired.

This is where software performance testing comes in. Testing your software for performance gives you opportunities to address performance-related issues before releasing your software to the public. As a result, your software will run well. Your users will be happy with your product, and more people will buy or sign up for your software and its updates.

What Is Performance Testing in Software Testing?

Software performance assessment is a critical part of quality assurance for apps and software. It is a way of checking an app, utility, or system software’s functionality. Performance tests evaluate functionality using various metrics that indicate a software’s speed, loading time, system stability, and co-utility with other types of software.

Software performance testing is quantitative. Testers will perform performance analysis using other software and in different settings. The settings in which testing is performed include lab settings where the system environment has controls and productivity settings.

Performance testing is effective when the right standards are in place. For this reason, software system performance testers must identify the parameters for measurement. These are the KPIs or key performance indicators. We’ll talk about these later.

Here are the key takeaways of performance testing:

  • It evaluates how well a certain type of software works.
  • Performance testing is metric-based, evaluating software performance based on quantitative metrics.
  • KPIs are the focal points of software performance testing measurements.
  • KPIs are quantitative standards that indicate software performance, stability, and speed.
  • Performance testing in software testing may either be in a lab environment or in a productivity-based environment.

Issues That Require Performance Testing

Earlier, we talked about how performance testing allows testers and devs to address problems before the software’s release date. However, what’s being tested during performance testing?

Below are some of the problems devs and testers look out for during software performance verification:

  • Problems With Load Times

    One of the first questions developers and testers will ask is: “How fast does the software load? Does it load easily?”

    The reason why testers test loading times is that users will likely prefer software with seamless loading. Software that loads quickly will cater to the needs of time-crunched users.

    When software loads in just seconds, it will tick the first user experience box. On the other hand, a long loading time will indicate the need for optimizations.

  • Problems With Response Times

    After determining the software’s loading speed, devs and testers will evaluate the software’s responsiveness. Like with the loading speed, responsiveness is an essential metric to measure.

    For more on other vital metrics for software performance testing, check out our checklist for effective performance testing.

    Responsiveness is more than whether or not an app or utility software responds to input. After all, software that performs a task slowly after the required input is still responsive. To ensure that the software caters to the needs of users, testers use response time as a metric.

    Response time is the amount of time it takes between the input (like a click) and the software’s activity. The shorter it is, the better. The longer the response time is, the less responsive the software is.

  • Memory Issues

    Memory-related issues include clutter from circular data and increased lag time from data swapping. These problems can render software unresponsive. In the worst-case scenario, memory issues will cause utility or application software to crash or not load at all.

    Memory issues are one of the most detrimental problems for software. For this reason, testers make it one of the focal points of performance testing. When software performance testing takes place without memory checks, problems occur, and the software won’t be fit for public use.


Types of Performance Tests

Different software types will warrant different tests. However, for the most part, you’ll find the following types of tests in almost every software performance test.

These tests help devs and testers evaluate various aspects of system, utility, and app software types.

  • Load Testing

    Load testing is all about determining the load speed of an app or software. Besides loading time, devs and testers will also be evaluating how the software loads after input. Load testing is a crucial part of every software’s performance testing. It’s a software performance test that gives devs and testers insight into many of a software’s back-end problems.

  • Stress Testing

    Many types of software will function well in ideal conditions — and even when they’re not used to their peak capacity. However, what separates great software from mediocre software is the performance at peak capacity. This is where stress testing comes in. During stress testing, devs and testers will push an application or software to the limits of its operation. As they do this, they’ll look for consistency in how the app or software performs during the entire stress performance testing phase.

    Stress testing is essential for most types of software. However, it’s a particularly important part of software performance testing when the software is web-based and used by many people simultaneously. Stress testing is also key for any app with online APIs due to its high multi-server usage.

  • Spike Testing

    Another way to “stress” an app or software is with sudden dips and peaks in use. This is where spike testing comes in.

    Spike testing involves checking an app or software performance after a sudden drop or surge in usage. Devs and testers will use spike testing during performance testing to evaluate how well a type of software performs with drastic traffic or use changes.

    Spike testing helps with benchmarking by helping devs determine your app or software’s capacity. Regardless of the type of software you're about to release, spike testing will always be a crucial part of the software performance testing process.

  • Scalability Testing

    Scalability testing and spike testing go hand-in-hand. Scalability testing helps devs evaluate how well your software adjusts to sudden peaks and drops in usage. As part of performance testing in software testing, scalability testing exposes deficiencies in adjustments. These gaps can be problematic when you’ve got an app designed for simultaneous usage.

    Scalability testing also reveals problems with how your software integrates with servers, giving you ample opportunities to address issues on the back end.

    Scalability testing is essential for web-based apps. It’s also a must for system apps that will have many users at a time.

  • Volume Testing

    Volume testing or “flood performance testing” involves the software’s evaluation after the “flooding” of data. Volume testing allows devs to assess your application or software’s behavior after massive data exposure.

    Volume testing will reveal various problems. One type of problem that surfaces during volume testing is an issue involving memory. Whenever an application or software crashes due to increased user demand, the software may have problems involving memory dumps or circular memory.

  • Endurance Testing

    Lastly, performance testing must include how well a site can hold up over time. For this part of performance testing in software testing, we’ve got endurance testing. Here’s how endurance testing works:

    Testers will run the software with some sort of load. The load will often be in the form of virtual users. The testers will then assess the performance of the software over time. The longer the software performs, the more “durable” or “enduring” it is.

    Endurance testing helps reveal various problems like memory leaks. Other problems devs can find during this part of performance testing include database connection problems and performance degradations like lag time.


Software Performance Testing Process

Now that you know what tests to expect, you must know how to test your software. There’s a process you must follow during performance testing to streamline your testing process.

Devs and testers will have their respective ways of doing it. Nevertheless, you can’t go wrong with the steps laid out in this section.

  1. Identify the Test Environment

    Testing environments or staging environments are the software and hardware tools devs use to create software. When you identify a testing environment, you’re also asking questions about what software and tools to use for software performance testing.

    Besides identifying what you need to test your software, you also need to know what to monitor. This brings us to the next step in the performance testing process.

  2. Identify KPIs

    KPIs are measurable indicators of your software’s performance. Think of them as the vital signs of your app or software.

    The KPIs you’ll monitor will depend on your app or software. In general, KPI identification will include all or a combination of the following during performance testing:

      • Wait time
      • Response time
      • Average load time
      • Error rate
      • Maximum concurrent users
      • Requests per second
      • Passed or failed transactions
      • Throughput
      • Memory utilization
      • CPU utilization

    We’ll talk about each KPI in detail later on. In the meantime, just know that KPIs are a sign of your software’s health. For this reason, checking KPIs will be a major part of performance testing in software testing.

  3. Plan and Design Tests

    After identifying your KPIs and test environment, you must set up your tests appropriately. With your KPIs identified, assign the appropriate tests. You may need to consult your in-house dev team for this.

    After determining the tests to perform, have metrics in place. Metrics allow you to establish a standard for judging software performance during performance testing. Without metrics, you’ll receive numerical values of KPIs that won’t tell you anything about the results of your performance testing.

  4. Configure the Test Environment

    The tools and software you’ve prepared for performance testing must coincide with the metrics or KPIs you’re measuring. Prepare your performance testing software and any necessary hardware to perform your desired tests.

  5. Implement Design

    After you’ve set everything up, you’re ready to conduct software performance testing. Before running your tests, consult the testers and dev team for some last-minute preparations and checks.

  6. Run Tests

    As you run your tests, ensure that you or the testers are monitoring data at every step of the performance testing process. Different tests will generate different results, so it’s crucial to have multiple teams or individuals performing tests.

  7. Analyze, Refine Strategy, and Retest

    By the end of the performance testing process, you’ll have access to data that tells you about your software’s performance. From here, you will have several options.

    If your software test reveals problems, you may tweak your app or software to optimize its performance. After the necessary optimizations, you can retest.

    Otherwise, you may find that some of your testing parameters weren’t the best for your KPIs. You can then refine your strategy, change your testing environment, and retest.

    Either way, you can expect to retest and re-evaluate data at various stages of the software performance testing process.


Performance Testing KPIs

Earlier, we mentioned that software performance evaluation involves the assessment and analysis of KPIs. KPIs are indicators of your software’s health and performance.

Monitoring them will provide useful insight into what needs fixing or optimizing. Testers and devs will judge the performance of software based on nine KPIs. Here are the KPIs you must keep tabs on throughout the performance testing process.

  • Wait Time

    Wait time refers to the time it takes for software to return a byte after a request. It’s one of the indicators of an application’s speed and responsiveness. A long wait time means that it takes a while before the app receives the first byte. This can signal interconnectivity or API-related problems or issues with the code.

  • Response Time

    Response time is a user-centered metric. It’s the time it takes for an application or software to perform a certain action after input or request.

    The longer the response time, the less likely a user will favor the app or software. The shorter the response time is, the more responsive the app will be. As a result, the app or software will show the earliest signs of providing a positive user experience.

  • Average Load Time

    Loading time is also a user-centered metric as users favor software or apps that load quickly. However, loading time can vary for many reasons unrelated to the software or app. Instead of testing loading time in one instance, devs determine average loading times.

    When testing for average load time, devs will boot an app or software several times. The testers or developers will then record the loading times and get the average. As with response time, developers will want the app to have short loading times.

  • Peak Response Time

    The peak response time refers to the longest amount of time it takes for apps or software to respond. Long peak response times are a sign of memory or code-related issues.

    Ignoring this metric during performance testing may result in an application or software that takes too long to respond. This carries over to longer response times and will render an application or software undesirable for users.

  • Error Rate

    At times, the software won’t yield quick requests or responses. When this occurs, it’s an error. Developers establish a software’s propensity for errors by testing its error rate. When software yields a high error rate, it’s a sign that it isn’t ready for use. Often, error rates indicate coding-related issues that the developers must fix.

  • Concurrent Users

    Applications and software will have many users at a time upon release. For this reason, developers must include concurrent users as a metric for performance testing.

    Concurrent users refer to the number of users a software can accommodate before it begins to suffer in performance. As a metric, it indicates the maximum load an application or software can handle in one timeframe. This KPI also goes by the name “maximum load size.”

  • Requests per Second

    Besides the number of concurrent users, developers must also test for the number of concurrent requests. The KPI that indicates the number of concurrent requests is known as requests per second.

    Requests per second refer to the number of inputs a software can handle each second. The higher this value is, the more responsive the application or software is to many users.

  • Passed or Failed Transactions

    This KPI refers to the number of successful and unsuccessful inputs. The response of an application or software determines the success of an input or request. A passed transaction occurs whenever the application generates an appropriate response. On the other hand, an application generates a failed response when the input results in an error.

  • Throughput

    There’s a close correlation between throughput and passed or failed transactions. Throughput is an indicator of how many transactions a type of software or application can process. Often, developers measure this throughout the performance testing process. Testers use kilobytes per second as the unit of measurement for throughput.

  • Memory Utilization

    Memory utilization is one of the determinants of a software’s responsiveness and function. It refers to how much memory a software or application uses to run in the background or perform an action after input.

    Memory utilization readings can reveal memory leaks that make an application “buggy.” The readings can also show if an application uses too much RAM.

    By testing a software’s memory utilization, developers can identify areas to declutter. If not, developers can create hardware recommendations for users. Often, the recommendations may be in the RAM or memory hard drives.

  • CPU Utilization

    CPU utilization shows how much of a CPU’s capacity an application or software uses. Developers assess an application’s CPU utilization during a request and as the software runs in the background. The latter is especially true for system software.

    The main metric developers use to evaluate CPU utilization is time. More specifically, testers check the time it takes for the CPU to process a request made on the software or application.

    CPU utilization can also help developers identify memory issues and code-related glitches. The findings can also help developers create hardware recommendations.


Why Should You Automate Your Performance Tests?

Performance testing in software testing is a crucial procedure before the release of any software or application. Because performance testing is so important, developers and testers work around the clock, calibrating environments and monitoring KPIs.

Developers and testers fulfill a vital role in the performance testing process. However, software performance assessment involves test environment configurations that may come out incorrect the first time. Also, KPI benchmarking can be time-consuming and problematic when external factors come into play.

As a business owner or CEO, you need to optimize efficiency wherever you can. One of the ways you can cut your dev team some slack is with automation.

Automating your performance testing provides several benefits that you may not have considered until now.

Let’s begin with how automation prevents software from deteriorating.

  • Prevent Performance Relapse

    Over time, your software will undergo upgrades. Every patch and software expansion will introduce additional RAM requirements that can cause your software or application to deteriorate.

    To prevent software from deteriorating, you may have to conduct performance testing before and after you add the updates. By automating your software performance testing, you’ll get on top of performance issues faster than you would if you relied on your dev team.

  • Improve User Experience

    Automation allows your dev team to run multiple tests simultaneously. As a result, automated performance testing enables you to monitor your software’s KPIs from both a developer and user standpoint. From the data, you’ll determine which parts of your software need improvement — in a fraction of the time.

    The product then becomes an application or software that provides a positive user experience.

  • Prevent Launch Failures

    Software launches are prone to unforeseen issues. Issues that accompany an app or software’s release can include high error rates, lag time, and long wait times that go undetected during manual software performance testing.

    Whenever a company releases software with these problems, everyone — both the company and customers — suffers. With this in mind, you must ensure that your software performs at its peak before you release it for public use.

    With automation, you can run multiple simulations and tests using various environments. By testing your software’s performance across multiple testing environments, you’ll see potential pitfalls before the software’s release. As a result, you can address problems with the code or API before launching your software.

  • Avoid Manual Missteps

    Human error will always be a factor in any software performance testing process. Although minimizing human error is possible, eliminating it will be challenging and expensive. Luckily, automation allows you to minimize the effect manual errors have on your software performance testing.

    Automation takes the guesswork out of your performance testing. All your dev team needs to do is configure your performance testing software and monitor the KPIs. By letting the performance testing software do the testing, you can avoid manual missteps throughout your performance testing.

  • Eliminate All Bottlenecks

    Performance bottlenecks occur due to faulty lines of code. While your dev team can spot this, identifying bottleneck-causing code can be time-consuming. Worse yet, correcting the code and testing it will take some time.

    Automating your performance testing solves this problem completely. By entrusting your testing with performance testing software, your team’s troubleshooting time will drop significantly. Also, your developers and testers will identify all problematic lines of code that they may otherwise miss without automated performance testing software.


Top 5 Performance Testing Tools

By now, it’s clear that effective performance testing is all about the performance testing software you use. By using the right tools for the job, your dev team can streamline the performance testing process, giving you a fully functional piece of software that’s glitch-free.

What are the best tools to use for software performance evaluation? Below are our five picks for the best software performance testing tools available.

  1. Apache JMeter

    Apache JMeter tops the list as one of the most intuitive and accessible tools for software performance testing. As an open-source website performance test software, Apache JMeter is excellent for cross-platform load testing.

    Apache JMeter also works well with nearly every network protocol. It’s compatible with HTTPS, FTP, LDAP, TCP, and many other commonly used network protocols. Apache JMeter also integrates well with mail protocols and shell scripts.

  2. Yandex Tank

    This tool has been making performance testing in software testing possible since its development in the early 2000s. Despite being one of the older software performance testing tools available, it has undergone multiple upgrades to accommodate the demand for better integration and flexibility.

    Yandex Tank integrates well with other performance testing tools like Apache. Also, Yandex has several automated features like auto-test stop and server monitoring. It is an excellent performance test software to use if you’re testing a Python-based app.

  3. Gatling

    Like Apache JMeter, Gatling is another open-source performance test software designed for load testing. However, what separates Gatling from its Java-based counterpart is its high-load capacity.

    Besides performing under high stress and load, Gatling also provides added visualization features for data. Adding to the performance software tool’s convenience factor is its automated report generation feature.

    All in all, Gatling gives you massive load-testing coverage and automated reports. All your team needs to do is sit back and wait for the data.

  4. Locust

    Locust is one of the most popular website performance test software available. Like the other performance testing tools on this list, Locust is open-source. Locust outperforms many performance testing tools in its ability to function across platforms.

    Programmers can easily write programs to test various software using Locust. However, where Locust truly shines is in its ability to test software written in Python. This makes it an excellent option for testing web-based applications or extension apps.

    Written with Flask, Locust functions on the Flask server. As a result, you don’t have to worry about server-related issues when you test using Locust.

  5. K6 Performance Testing

    When it comes to evaluating software at its most granular level, few software performance testing tools can match K6 Performance Testing.

    K6 Performance Testing is another open-source tool to help developers identify code-related problems. With this performance testing tool, developers can also customize KPIs and other metrics for tailored software performance tests.

    K6 Performance Testing enables devs to write code and test it. It’s the right software performance assessment tool for you if you’re unable to outsource independent performance testing.


Key Takeaway

Software performance testing is a metrics-based process, requiring your developers to keep a close eye on KPIs. To achieve accurate results, developers must test your software in an environment with all of the necessary tools for the task.

Software performance testing is a critical part of your software’s launch. Automation enables you to save time, money, and manpower as you maximize the ROI of your new software.

The tools we’ve mentioned here will help boost your software performance testing efforts. However, you’ll always run into unforeseen obstacles. If you need help with your software’s quality assurance, choose a company that provides comprehensive and reliable software performance testing services. Reach out now for a half-hour consultation, and let us help you glitch-proof your software.


This publication is for informational purposes only, and nothing contained in it should be considered legal advice. We expressly disclaim any warranty or responsibility for damages arising out of this information and encourage you to consult with legal counsel regarding your specific needs. We do not undertake any duty to update previously posted materials.