Load Testing

Load Testing

What is load testing?

In the sphere of professional software testing, load testing comes to represent an area that is a type of non-functional testing. What do we mean by this and what is load testing exactly? 

According to TechTarget, load testing is “the process of subjecting a computer, peripheral, server, network, or application to a work level approaching the limits of its specifications. Load testing can be done under controlled lab conditions to compare the capabilities of different systems or to accurately measure the capabilities of a single system. Load testing can also be done in the field to obtain a qualitative idea of how well a system functions in the real world.” 

To complement the explanation of what is load testing, we add the fact that load testing is a part of the general process known as performance testing. Load tests are a type of software testing used to understand and model the expected usage of a software program by simulating a real-world load of multiple users accessing the program simultaneously. The load testing practice is designed and used to evaluate how a software system behaves during normal and high loads to determine if it can handle high loads during high demand periods.

Load testing can be performed on end-to-end software systems or on small components to measure speed, capacity and response time to check for bottlenecks, unstable performance, and maximum operating capacity.

It is specifically valuable to perform load testing in software development projects that are nearly done, and we’ll explore more about the benefits and importance of performing load testing as part of the Software Development Lifecycle (SDLC) in an upcoming section.

Throughout this article, we will take a closer look at load testing to unveil in-depth what it is and what it involves. Let’s get to it.

Why load testing is an important part of the Software Development Lifecycle?

Load testing is important in the Software Development Lifecycle because of the following reasons:

  • It simulates real user scenarios.
  • It evaluates how the performance of an application can be affected by normal and peak loads.
  • It helps save money by identifying bottlenecks and defects on time.

It is always advisable to test, analyze, and fix bugs during the Software Development Lifecycle before actually deploying an application in the real world and have it fail with end users. As part of a continuous integration cycle, it is good practice to run automated load tests to see if code changes affect performance.

Building a proper strategy for load testing

Software applications and systems are information-intensive and are ultimately created to provide a solution to a problem. That is why it comes as no surprise that they require a robust strategy to achieve effective implementation and successful functioning. 

The same goes for load testing, especially given the importance it holds in the overall process of creating software and having it deliver substantial value. Load testing helps shape the experience users receive by defining the parameters under which it performs adequately.

Testing is as valuable as the testing plan. It is very helpful to build a test plan that is in sync with testing requirements and that focuses on the outcomes you want to obtain. Strategizing test plans helps teams follow through the exact necessary tests to get reliable results from the testing activity.

The strategy for load testing considers all potential pitfalls and challenges that can create bottlenecks or hinder performance in a software application. A thorough strategy acknowledges every feature, functionality, and component of the application in order to build a comprehensive plan to design a realistic workload and gauge performance.

Thus, before you jump into load testing, it is highly desirable to first evaluate the best approach to execute load testing with a strong strategy that considers the entire nature of the application along with business goals. With a comprehensive strategy, you streamline testing and can save a significant amount of time and investment on unnecessary tests and efforts.

Manual load testing

Load testing can be performed manually or with automation testing tools. In the realm of manual load testing, loads can’t be particularly excessive since, well...everything is done manually. Thus, it is highly unlikely that large amounts of load can be placed on an application given the volume of manpower that it would require. For this reason, manual load testing tends to be expensive.

Custom load testing tools

With many open source load testing tools available, you may find yourself in a scenario where you require a little something extra that accommodates larger and more complex testing scenarios that entail large amounts of data. If that is the case, then you may require a custom load testing tool that is specifically tailored to your unique set of needs - these custom solutions are built in-house. Custom load testing tools come at a price and thus represent an increase in investment, both in terms of money and effort. But that investment is paid off by leveraging a tool that is specifically customized to meet your every need, one for one.

Open source load testing tools

With a lot of open source load testing tools to choose from, it can be daunting to select the best load testing tool for your unique set of needs. Oftentimes, you’ll do well with a free or open source load testing tool that gets the job done without much customization, but with enough features to deliver the right results. Open source tools tend to be the right solution for tech-savvy testers who are looking for a small or simple scale test.

Top examples of open source load testing tools include:

Corporate and enterprise level load testing tools

Enterprise-level load testing tools are designed with reliability in mind as well as precision, in-depth testing capability, and most importantly, large scale. An enterprise-level tool must be capable of handling heavy loads with enterprise-grade accurate results,  
Top examples of enterprise-level load testing tools include:

Analysis of load testing results

Regardless of how many tests you perform on a software system, they would be nothing without properly interpreting and analyzing the results they yield. After load testing is executed, it is critical to collect all results, from response time to system resources, and pinpoint any bottleneck or defect that was identified to raise its corresponding ticket incident to have it fixed and solved.

Additionally, root-cause analysis can be performed to understand the bottleneck or defect from its origin and thus prevent future errors.

Analyzing load testing results helps create a strategy to fine-tune the application and apply the necessary corrections that must be conducted to deliver high-quality performance.

Performance, load, and stress testing

The terms performance testing, load testing, and stress testing are sometimes used interchangeably when in reality they differ greatly from one another.

For starters, performance testing is a more general term that encompasses the activities of load testing. 

  • Performance testing is the practice in which tests are performed on a software system to determine speed, responsiveness, and stability. In essence, performance testing is designed to provide an indication of how software applications behave under normal circumstances.
  • Stress testing, on the other hand, is a practice that evaluates the extent to which a system functions under extreme workloads or if the software/hardware has been compromised in any way. In essence, and similar but not equal to load testing, stress testing increases the load on an application until it collapses to establish its breaking point.
  • As we’ve explained, load testing is used to understand and define the maximum amount of work a system is capable of sustaining without significant performance degradation. In essence, load testing measures response time when a software application is subjected to unusual loads.

Load testing vs performance testing

Rather than thinking of load testing vs performance testing, these concepts sometimes end up being used with a sense of confusion as they are somewhat similar. But let’s clear the air.

Performance testing is a much broader concept than load testing. Overall, performance testing evaluates how an entire system performs and measures how it responds under a specific workload.

Load testing puts exhausting amounts of demand on a system to measure how it responds under both normal and peak loads.

Cloud system and load testing: scalability

Driving load tests on cloud systems offer the possibility of determining the scalability point of software. Regardless of whether the software is consumer-driven, there will come a time when it is very likely that it will reach its limit. Load testing in cloud systems enables the testing staff to evaluate performance scale peaks to assess at what point the system needs to grow or add extra resources such as storage or bandwidth.

Load testing in cloud systems can be a complex task, but it brings numerous benefits such as reduction of short-term investment, ease of scalability, and the on-demand factor of the cloud that is inherent to its nature. As companies demand more from their cloud infrastructures, it is important that load testing keeps up the pace and continues to be an essential step in any SDLC process.


Load testing should definitely be a part of your strategy to make your software application more efficient, effective, performance-oriented, and consumer-driven.

Testing provides insights, and those insights can make or break your application when it comes to correcting defects or creating contingency plans for heavy traffic. So, don’t think twice: load testing is a great investment for the overall performance of your software application.

Given the importance that load testing represents the overall success of an application’s performance, we invite you to consider this important testing practice as a regular tool in your arsenal for software building. Let us help you with your testing needs. At Svitla Systems, we have specialized teams of professionals who are experts in load testing and are at the ready to assist you in your next project.

by Svitla Team

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