Understanding your results

LoadRunner Cloud allows you to see the results of your test runs in the graph dashboard or in a report view.

What is the dashboard?

This section describes the new dashboard, as shown by default in the LoadRunner Cloud Dashboard tab.

The new dashboard shows more information than the dashboard from earlier versions of LoadRunner Cloud. To view the older dashboard, set the toggle to OFF. For details, see Previous dashboard.

The LoadRunner Cloud Dashboard tab displays graphs that can help you analyze the performance of a selected run for a load test.

The Dashboard tab is comprised of two panes.

  • The left pane displays a list of metrics that you can choose to display.
  • The right pane shows the actual graphs.

You can also set the scale and test duration that you want to view.

For details, see Dashboard.

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What is the report view?

This section describes the new report, as shown by default in the LoadRunner Cloud Report tab. The new report shows more information than reports in earlier versions of LoadRunner Cloud. To view the older report, set the toggle to OFF. For details, see Previous report.

LoadRunner Cloud's Report tab shows statistics and performance data for test runs.

The Report tab is comprised of two panes.

  • The left pane displays a list of built-in reports that you can choose to display.
  • The right pane shows the actual reports.

You can also order and sort the results.

The available reports are: Summary, Top 10 Transactions, Passed & failed Transactions per second, Errors per second, Errors Summary, Throughput & Hits per second, Scripts, Distribution, and HTTP Responses.

For details, see Report.

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SLAs

Service level agreements (SLAs) are specific goals that you define for your load test run. After a test run, LoadRunner Cloud compares these goals against performance related data that was gathered and stored during the course of the run, and determines whether the SLA passed or failed.

In LoadRunner Cloud you set the following goals:

Goal Description
Percentile The percentage of transactions expected to complete successfully, by default 90%.
TRT (transaction response time) seconds percentile

The expected time it takes the specified percent of transactions to complete (by default 3 seconds). If the percent of completed transaction exceeds the SLA's value, the SLA will be considered "broken".

For example, assume you have a transaction named "Login" in your script, where the 90th percentile TRT (seconds) value is set to 2.50 seconds. If more than 10% of successful transactions that ended during a 5 second window have a response greater than 2.50 seconds, the SLA will be considered "broken". It will show a Failed status. For details about how the percentiles are calculated, see Percentiles.

Percent of allowed failed transactions The percent of allowed failed transactions, by default 10%. If the percent of failed transaction exceeds the SLA's value, the SLA will be considered "broken" and will show a Fail status.

You can set a separate SLA for each of your runs. You can also select multiple SLAs at one time and use bulk actions to apply one or more actions to the set. For details, see Configure SLAs.

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Percentiles

A percentile is a statistical tool that marks the value into which a given percentage of participants in a group falls. In the context of test runs, if you check against a 90th percentile, you are looking to see which tests performed better than 90% of tests that participated in the run.

There are several common algorithms used to calculate percentiles:

Algorithm Description
Average percentile over time This method calculates the average percentile over time— not the percentile for the duration of the test. The percentile is calculated per interval (by default 5 seconds). The dashboard and report show an aggregate of the percentile values.
Optimized percentile (T-Digest) An optimized (not average) percentile, based on the T-Digest algorithm introduced by Ted Dunning as described in the T-Digest abstract. This algorithm calculates percentile values for large raw data sets, as the ones produced by LoadRunner Cloud during each test run.

LoadRunner Cloud algorithm usage

For the Dashboard, LoadRunner Cloud uses the average percentile over time algorithm.

For Reports, tenants created before version 2020.05 (May 2020) use the average percentile over time algorithm.

  • Tenants created after May 2020, automatically use the optimized percentile (T-Digest) algorithm to calculate transaction percentiles.
  • Tenants created before version 2020.05 (May 2020) use the average percentile algorithm. To use the optimized percentile algorithm for these earlier tenants, you must enable the Optimized percentile (T-Digest) option as described in Set general test settings. By default, this option is not visible in the General settings. To display this option for tenants created before May 2020, open a support ticket.

Once the T-Digest algorithm is enabled, it will be used as the default for all new tests.

Note: If you have tests that were run with the average percentile over time algorithm, and then subsequently run with the optimized T-Digest algorithm, the grid will not display this column, and an informational message will indicate that the algorithms were different.

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See also: