Author: Ivan Lisitsyn

Performance glitches on charts
Testing practice WAPT usage

Performance glitches on charts

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When you load test a web application and gradually increase the number of virtual users during the test, you usually expect to see gradually degrading performance parameters such as response time. The number of pages (sessions or hits) per second will reach maximum in some moment and will probably stay the same for the rest of the test despite the growing load. This is simply because the site cannot serve more requests per second, so it has to postpone the new coming ones.

In reality you will probably see something like that, but only for a limited time. When the load goes even higher, you can get another picture that may seem surprising at first glance. It is illustrated by the following three charts. Black line in all charts represents the number of virtual users.

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How to analyze a load test report? Part 4: Response time.
Testing practice WAPT usage

How to analyze a load test report? Part 4: Response time.

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Let’s suppose that you have already resolved all problems related to unexpected errors in your test. I mean that your site may produce some errors on heavy load, but the emulation of the user sessions is performed correctly and the error rate is acceptable. If this is not the case, or you have any doubts, you may want to read my earlier posts here and here.

If the errors are not an issue, your next step is to look at the most evident indicator of the application performance – its response time. This term initially refers to a time required for your application to respond to a user action. This looks very simple, but you should keep in mind the following things, if you want to analyze the test results correctly.

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Connecting to WMI on a remote system
General WAPT usage

Connecting to WMI on a remote system

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Windows Management Instrumentation (WMI) is one of the common interfaces used to retrieve information from a Windows system. Such information can include values provided not only by the system itself, but by various software programs running on it. That is why WMI is widely used to monitor the performance and correct operation of the server components.

Many load testing tools, such as WAPT Pro, can monitor performance counters directly from the tested servers with help of WMI. The most useful counters are those representing CPU, RAM and network usage, but there can be other server-specific ones that you can easily retrieve.

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How to analyze a load test report? Part 3: Errors.
Testing practice WAPT usage

How to analyze a load test report? Part 3: Errors.

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If you see any errors after executing a load test, first of all you should check if this is a test design problem. I wrote about the most typical problems of that kind here.

Now let’s suppose that the test was designed correctly and any errors we see in the report are related to the load you created in the test. In other words, I would like to talk about errors that appear because of performance problems, not anything else. If you are not sure why an error takes place, try running the test with same profiles and a smaller number of users, and see if the same problem appears.

First of all I should note that there are different types of errors.

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WAPT Cloud: New benefits of our load testing solution
General Testing practice WAPT usage

WAPT Cloud: New benefits of our load testing solution

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In the last days of 2013 we released a cloud version of our load testing solution. It is based on WAPT Pro, all extension modules and x64 Load Engines, so it is the most feature-reach and powerful combination of all the components we have.

This on-demand load testing solution is offered through the Amazon EC2 Marketplace. This means that with few clicks you can get the full functionality of WAPT Pro running on a virtual system instance in the Amazon Cloud. To do this you need to have an AWS account, however it is also very easy to create one. We provide step by step usage instructions right from our web site.

Some experienced users already know that all our products can be used in any cloud or virtual environment. So, technically this release is not a big step forward. With new cloud version it is easier to start and configure the product, but this is not the actual benefit. What really makes the change is the pricing for the new solution, which is now based on the hour rates.

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