In this post we will be looking at two different subjects, these are performance comparison and Load Testing. Load Testing helps you to measure performance under the specific circumstances you have selected, whereas Performance measures the experience for a general range of users. The purpose of Load testing is essentially to put your website under pressure and compare it to see how it copes. It’s similar to traffic filling up a car park and seeing how long it takes before there is no room left, but instead we are putting our websites ‘under pressure’
When we need to check load time of a website or application, we can use different tools for that purpose. But first thing we need to figure out is, What are the best tools for performance and load testing? In this article, I would like to compare and contrast these two types of tests.
The biggest challenge facing developers today is how to differentiate between performance and load testing. This distinction is critical as one test could lead to a lot of confusion and wasted time, money and effort. While both performance tests and load tests measure application performance, the approaches are fundamentally different.
What is Performance testing?
Performance testing is a type of testing for determining the speed of a computer, network or device. It checks the performance of the components of a system by passing different parameters in different load scenarios.
Performance testing is key for understanding how your system works. Without good performance testing, you don’t know how your system will deal with expected—or unexpected—demands.
Performance Testing:
Performance Testing is a type of software testing that is carried out to determine system performance in terms of sensitivity, reactivity and stability under a particular workload.
When you want to find out how the components of a system are performing under a given situation, performance testing is the way to go. You’ll want to find out three key factors about your product:
- The scalability
- The resource usage
- The reliability
As a subset of performance engineering, this type of testing addresses performance issues in the architecture and design of the system. Using performance testing tools, we can begin practicing risk management.
Load testing and stress testing are merely subsets of performance testing. As such, performance testing is a wide term that encompasses:
- Spike testing
- Endurance testing
- Volume testing
- Scalability testing
How frequently you test performance depends on your development methodology:
- A team using a waterfall approach will want to test with each individual release.
- If they are using the agile methodology, performance testing should be a constant practice alongside development.
Why use performance testing?
Want to establish the benchmark behavior of your system? The first step to testing your functionality is performance testing. During performance testing, you’re looking to meet or exceed a number of industry-defined benchmarks.
Importantly, performance testing is not in any way aimed at finding defects with the application.
Rather, it’s meant to set the benchmark and standard for the application. The key is to ensure that utmost accuracy is observed during performance testing. Close monitoring is necessary for ensuring the performance of a system or application.
When setting a benchmark, examine attributes such as:
- Throughput
- Response time
- Speed
- Stability
- Resource usage
These are examples of KPIs—Key Performance Indicators. Essentially, performance testing analyzes KPIs like these.
Performance testing best practices
When or how often to performance test depends on what kind of testing you are doing. Here are some tips for getting the most out of your performance testing measures.
Your performance testing should not include any actual users. Performance testing should use software to measure how well it performs or does not perform. User Acceptance Testing (UAT) is when we start to use real software or system users to see how it performs in the real world.
Test as often as possible. There are specific times to test, usually near the last step. When it is time to test, do it repeatedly. Repeat tests over and over to get the most accurate results. If your application, software, or website can successfully pass the tests over and over again, you can tick it off as ready for the next stage.
Do not change what you are testing. When we make lots of changes to an experiment, it becomes more difficult to identify what exactly we’re testing. Between each test, your environment should stay the same. This includes the load or stress that you place upon the system.
Use automated tools to make the process as simple as possible. Automating your testing process will boost efficiency. You can:
- Save time and money
- Minimize navigating complex architecture
- Provide more accurate results faster
Common tools for performance testing include:
- Apache JMeter
- Ready API
- BlazeMeter
- Visual Studio Test Professional
- Micro Focus LoadRunner
What is Load testing?
Load testing is the process that simulates actual user load on any application or website. It checks how the application behaves during normal and high loads. This type of testing is applied when a development project nears to its completion.
Load testing and stress testing are two kinds of performance testing. Knowing when to use load testing and when to use stressing testing depends on what you need:
Load Testing:
Load Testing is a type of software testing which determines the performance of a system, software product or software application under real life based load conditions.
Load testing is the process of putting pressure on a software, system, or device to measure its response under an expected load.
By simulating production (pressure), load testing shows the behavior under normal and expected peak conditions. The goal is to ensure a given function, system, or program can handle what it’s designed for. This is important because when you’re building your product, you’re only accounting for a few individual users. Load testing helps you prepare for what happens when you deploy your product to hundreds or thousands of users.
More specifically, the goals of load testing include:
- Determining the upper limit of all the components of an application (the hardware, database, network, etc.). This test ensures that the application has the ability to manage any load it will be exposed to in the future.
- Detecting defects in applications that relate to buffer overflow, memory mismanagement, and memory leaks. Load testing is likely to expose a number of issues including bandwidth issues, load balancing problems, and the carrying capacity of the system.
Usually, you load test a system that is as close as possible to becoming a finished product, ready for deployment to the masses. It shows your team whether the product is working as expected and/or intended, under the given conditions.
How load testing works
During load testing, the system is taken through a steadily and constantly increasing load until it reaches the threshold. You want to find the weight limit—the weight (load) of activity that an application, software, or website can handle under normal conditions.
The weight limit should be our peak load. Load testing should help you identify:
- Page load issues
- System lag
- Additional issues arising when multiple users accessing the system
Good load testing probably looks something like this:
We have four bars to look at:
- Green means hits (visitors)
- Red means errors
- Yellow means response time
- Blue means users
This is a good experiment for a number of reasons. We want to see the blue and green lines climbing while the yellow one stays relatively flat. If the yellow line drops, we know that the software can’t stand up to high demands (users and visitors).
As we add hits to the software, the system should be able to withstand traffic until we reach our expected weight limit. Seeing a drop in the yellow line on the graph would indicate that there is a problem and that the weight limit is a lot lower than desired. If it can’t perform well with the expected load, there may be some serious problems in the design.
Of course, you want to know what will happen to the system when the traffic increases suddenly. You may not be able to detect some of these issues during development and testing. This could include testing for:
- Traffic from different or varying geo-locations
- Sudden spikes in traffic
When to load test
Load testing as a process doesn’t start till a project is close to its end. This is when system performance and actual user engagement can undergo accurate simulation and testing.
(Technically, you don’t have to wait till software development is completed before testing. You can test a specific component in a focused way for the load at any stage of the development process. Still, to test the demand of hundreds of thousands of users, it’s best to wait till development is nearly complete.)
Load testing tools usually mimic the actions of multiple concurrent users of the program, website, app, etc. It is a repeated procedure that involves collecting and monitoring both software and hardware statistics. Of particular interest are the:
- CPU
- Disk IO
- Memory of the physical servers
The test will also show the response time and throughput of the system along with other KPIs. When checking backend performance issues, the endurance of input over prolonged periods of time or simultaneous user input is important to understand. However, checking for things that could cause lag, broken functionality, or memory leaks before completing development is load testing in a limited form.
After analysis, the load testing software will generate a load testing report. Compare these results to your expected goals (benchmarks).
Difference between Performance Testing and Load Testing:
| Performance Testing | Load Testing |
|---|---|
| Performance testing is the process of determining the system’s performance that includes speed, reliability under varying load . | Load testing is the process of determination of behavior of system when multiple users access it at the same time. |
| In performance the load on which system is tested is normal. | In load testing peak load is used for testing. |
| It checks the behavior of the system under normal load. | It checks the behavior of the system under extreme load. |
| In performance testing, limit of load is both below and above the threshold of a break. | In load testing, limit of load is the threshold of a break. |
| It validates that the performance of system is proper. | It determines the operating capacity of the system or software application. |
| Speed, scalability, stability and reliability are tested during performance testing. | Only sustainability of the system is tested during load testing. |
| Performance testing tools are less costly. | Load testing tools are high costly. |
When do you use Performance Testing?
Performance testing is done to check the performance of website servers, database, and network. If you are adopting waterfall methodology, then it is important for you to check each time release of a new version. However, if you are using the agile software development approach, then you need to test application continuously.
When do you use Load testing?
Load testing is performed to determine how many users the system can handle. You can also check out different scenarios that let you focus on different parts of your system. Like the home page or checkout webpage on your website for web load testing. It also helps you to determine how the load builds and sustains in the system.
CONCLUSION
Performance and load tests are both aimed at measuring the behavior of an application or web site under heavy load. But they measure very different things:
Performance testing is the process of measuring performance under load. Load testing is a part of performance testing. The difference between performance and load testing is the amount of traffic used. In this article I’ll explain the differences between these two test types.