Walkthrough: Using the Virtual User Activity Chart to Isolate Issues

Article
09/29/2016

In this walkthrough you will learn how to use the Virtual User Activity Chart to isolate errors that occurred for individual virtual users that ran your load test.

The Virtual User Activity Chart lets you visualize the virtual user activity that is associated with your load test. Each row in the chart represents an individual virtual user. The Virtual User Activity Chart shows you exactly what each virtual user was executing during the test. This lets you isolate performance issues by seeing patterns of user activity, load patterns, correlate failed or slow tests, and see requests with other virtual user activity. The Virtual User Activity Chart is available only after the load after has finished running.

In this walkthrough, you will complete the following tasks:

Learn how to use the following tools associated with the Virtual User Activity Chart:
- Use the Zoom to time period tool to specify a specific time period on the chart that you want to analyze.
- Use the Details Legend panel and the Filter results panel, to apply filtering to the chart to help isolate issues.
Use the Virtual User Activity Chart to analyze an error that occurred for a specific virtual user and view the problematic error type details.

For more information, see Analyzing Virtual User Activity in the Details View.

Prerequisites

Visual Studio Enterprise
Complete these procedures:
- Record and run a web performance test.
- Create and run a load test

Open the ColorWebApp Solution Created in the Previous Walkthroughs

Open the solution

Start Visual Studio.
Open the ColorWebApp solution that contains the LoadTest1.loadtest. This load test results from conducting the steps in the three walkthroughs that are listed at the beginning of this topic in the prerequisites section.

The remaining steps in this walkthrough assume a Web application named ColorWebApp, a Web performance test named ColorWebAppTest.webtest and a load test named LoadTest1.loadtest.

Run the Load Test

Run your load test to collect virtual user activity data.

Run the load test to collect virtual user activity data

In the Load Test Editor, choose the Run button on the toolbar. LoadTest1 starts to run.

As in the previous walkthrough, you should see some threshold violation icons appear on the Page Response Time graph. For more information, see Create and run a load test.

Isolate Issues in the Virtual User Activity Chart

After you have run your load test and collected the virtual user activity data, you can view the data in the load test results by using the load Test Analyzer's Details view in the Virtual User Activity chart. Additionally, you can use the Virtual User Activity Chart to help isolate performance issues in your load test.

To use the Virtual User Activity Chart in your load test results

After the load test is finished running, the Summary page for the load test results is displayed in the Load Test Analyzer. Choose the Graphs button on the toolbar.

The Graphs view is displayed.
On the Page Response Time graph, right-click near one of the threshold violation icons and select Go to user detail.

Note

You can use the Details button in the Load Test Editor's toolbar to open the User Activity chart too. However, if you use the Go to user detail option, the Virtual User Activity Chart will automatically zoom in on the part of the test that you right clicked in the graph.

The Details view is displayed with the Virtual User Activity Chart focused on the time period when the threshold violations occurred.

On the y-axis, the horizontal plots represent individual virtual users. The x-axis displays time line for the load test run.
In the Zoom to time period tool below the Virtual User Activity Chart, adjust the left and right sliders until both are close to the threshold violation icon. This changes the time scale in the Virtual User Activity Chart
In the Details Legend, select the check box for (Highlight errors). Notice that the virtual user who caused the threshold violation is highlighted.
In the Filter results panel, clear the check boxes for Show successful results and HttpError but leave the ValidationRuleError check box selected.

The Virtual User Activity Chart displays only the virtual users that spent more than 3 seconds on the Red.aspx page as specified by the threshold violation configured in the previous walkthrough. For more information, see Create and run a load test.
Rest the mouse pointer over the horizontal line that represents the virtual user with the validation rule error for the threshold violation.
A tool tip is displayed with the following information:
- User Id
- Scenario
- Test
- Outcome
- Network
- Start Time
- Duration
- Agent
- Test log
Notice that Test log is a link. Choose the Test log link.
The ColorWebTest Web performance test that is associated with the log opens in the Web Performance Test Results Viewer. This lets you isolate where the threshold violations occurred.

You can use various settings in both the Details Legend and Filter results panels to help in isolating performance issues, and errors in your load tests. Experiment with these settings and the Zoom to time period tool to see how the virtual user data is presented in the Virtual User Activity Chart.