While doing performance testing, it is important to understand the term “concurrent” as it pertains to different aspects within performance testing, and is often misunderstood, causing some significant measures to be overlooked. Do you ever wonder how your website is performing on end user devices? Or how do you plan for increasing website traffic? Or even how to solve website problems that are seemingly invisible but impacting your overall business? The answer to these questions is performance testing.
Performance testing has been around forever but evolving with newer technologies every day. At its core, performance testing is done by simulating real users to interact with the website using scripts. This interaction data is then captured and analyzed for insights on different aspects of website and application performance such as response time, accessibility, reliability, uptime, resource usage, and scalability, etc. Performance testing is done to make sure that the website is in a stable state with performance criteria and how to improve and scale when the need arises. More importantly, it will provide useful data about how the system is performing under projected workloads. Performance testing will also uncover inconsistencies, inefficiencies, and usability issues when multiple requests are made concurrently.
Fundamental Performance Problems and Metrics
When conducting load and stress testing, understanding key performance metrics is essential for evaluating the health and efficiency of your system. These metrics provide actionable insights into how well your website, application, or API performs under various conditions. Let’s explore the most important ones:
Load Time
Load time measures how long it takes for a web page or application to fully load and become usable for end users. A fast load time is critical for providing a positive user experience, as even a delay of a few seconds can lead to frustration and increased bounce rates.
Response Time
Response time refers to how quickly the system reacts to user requests such as loading a page, submitting a form, or fetching data from a server. Consistently low response times are key to ensuring smooth user interactions especially during peak traffic periods.
Resource Utilization and Bottlenecks
This metric tracks how effectively your system uses its resources which includes CPU, memory, disk I/O, and network bandwidth. Identifying bottlenecks which are areas where resources are overutilized or inefficiently used helps improve system performance and reliability.
Scalability
Scalability assesses how well your system can handle increased user loads by allocating additional resources. A scalable system should maintain performance levels even as the number of users or workload grows. This is critical for businesses planning for growth or seasonal traffic surges.
Throughput
Throughput measures the number of requests or transactions the system can handle per second. High throughput indicates that your system can process a significant volume of data and user actions without degradation.
Error Rate
The error rate tracks the percentage of failed requests or transactions compared to the total number of requests. Monitoring this metric helps identify issues such as server errors, timeouts, or broken APIs that could disrupt the user experience.
Peak Response Time
Unlike average response time, peak response time identifies the slowest response experienced during testing. It highlights performance issues under stress or load and can indicate areas needing optimization.
By monitoring and analyzing these metrics, teams can identify performance bottlenecks, improve scalability, and deliver a better user experience. Combining these insights with robust testing practices ensures your system is ready to perform reliably under all conditions.
Concurrent HTTP Connections vs. Concurrent Browsers vs. Concurrent Users
Concurrent HTTP
Concurrent HTTP refers to HTTP requests made at any point in time. For example, let’s say there are 10000 users with valid sessions and 100 users are requesting to read the same resource over HTTP at any point in time then we have 100 concurrent HTTP requests.
Concurrent Browsers
Concurrent browsers refer to the number of browsers with valid sessions at any point in time. They can send any number of requests to the server at any point in time.
Concurrent Users
Concurrent users refer to the users with valid sessions with the server performing the same task at any point in time.
Usually, people get confused with concurrent users and simultaneous users as these both are used interchangeably, but in performance testing these two terms have different meanings. Let’s take a look at an example:
Suppose there are 1,000 different users with a valid session with the server. Each of these users is performing different operations like sign-in, checkout, messaging, shopping, etc. These are called concurrent users, which are essentially the number of users with valid sessions in the server. Now, it might happen that 100 out of these 1000 users are performing checkout operations at the same point in time. Then these 100 users would be simultaneous users. Simultaneous users are often very less than concurrent users and occur infrequently.
Load Testing: Speed, Scalability, and Stability
Load testing is one of the most important type of performance testing to testing the website/application under high traffic load. The data gathered from this testing is analyzed and projected to figure out the problems that may occur when high number of real users access your website. It is helpful to remove bottlenecks and optimize transactions along with planning for future scalability of website/application infrastructure. Let’s look at some basic load testing types, how they are different, and their importance.
HTTP Load Test
HTTP load testing is usually done for identifying how many concurrent HTTP requests the server can handle. It can also be approached as maximum number of requests per second. On a granular level, there might be different types of requests, such as read, write, commuting, etc. Finding out the limit for each specific request can give you more insight into what optimization and resource planning you need to do. For example – the number of requests per second can be higher for a read HTTP requests but it would probably lot less for commuting intensive requests.
Web Page Load Test
A web page load test is done for any single page loading time. For example, if you have an e-commerce website, you want to check for individual product page load time, cart page load time, checkout page load time to enhance and improve customer experience. If you product page load is fine but you ignore the optimization on cart page, it would definitely result into sales loss.
Web Application Load Test
A web application load test is done for measuring the first load of your web application. It is different from page load time where you do it for every other individual page. When a web application starts, it pulls out different resources, initiates few site-wide services, calls third-party services, and so on before it finally loads. It should be your first focus to optimize web application load time to prevent churning.
Final Thoughts: Concurrent HTTP vs. Concurrent Browsers vs. Concurrent Users
Load testing is a necessity that helps developers and architects in optimization and resource planning. For web applications that expect peak traffics, it becomes even more important. Apart from load testing, it is also important to regularly monitor your website or application for accessibility, speed, and uptime of third-party services. Don’t forget to load test and monitor your website or application from different geo-locations to improve it further for users as they might have specific performance issues derived from their location. Using a solution like LoadView allows you to easily load test all your web pages, applications, web services, servers, and APIs, with hundreds to thousands of concurrent HTTP connections or browsers.
Try the LoadView free trial and receive free load tests. Or schedule a live demo with one our performance engineers for a full walk through of the LoadView platform to see all the features and benefits the platform has to offer!