Regions of Interest

Updated: October 20, 2013

Regions of Interest is a new capability in WPA that enables the application of user-friendly labels to portions of the trace. These labels are applied by finding events that define the start and stop of a given region. The regions and their events are contained within a regions XML file. Microsoft provides some regions files for app analysis, and you can also define your own regions files for your scenarios or applications. This capability allows you to quickly and easily identify complex regions and greatly increases the speed and efficiency of performance analysis.

As an example, assume a scenario that contains several loading sequences, each of which is defined by one event, A, followed by another event, B. With Regions of Interest, you can apply a user-friendly "Loading" label to each of these A-B time spans. Now, instead of having to manually identify each of these event sequences, WPA automatically applies the "Loading" label, allowing you to quickly visualize where these events occur.

As another example, a user needs to analyze the performance of a particular Windows Store app. The application lifecycle can be broken down into several phases, such as launch, suspend/resume, and shutdown, each of which could have a corresponding region definition. With these region definitions, any user could easily identify where these lifecycle events occur.

To use Regions of Interest with WPA, you must have the following:

  • An ETW trace (.etl) file that was collected during the scenario of interest

  • A Regions of Interest definition file (.xml)

For information on creating a Regions of Interest file, see Creating a Regions of Interest File

You can use a Regions of Interest file to apply additional markup to an open trace in WPA:

  • From the menu, choose Trace, Trace Properties.

  • In the Trace Properties pane that appears, choose Add.

  • Navigate to and select the desired Regions of Interest manifest file (.xml), and choose Open.

  • The file is now added to the Regions of Interest Definitions listbox. Switch back to the Analysis pane by selecting the Analysis tab near the top of the window.

  • In the Graph Explorer, expand the System Activity node.

  • If your trace contains any of the regions that were defined by the manifest file, the Regions of Interest graph appears in Graph Explorer as the last graph under System Activity (immediately before the Computation category). Drag the graph onto the Analysis pane.

    If the trace does not contain any regions of interest, you will not see a Regions of Interest graph.

The Attributed CPU Usage table relies on regions of interest definitions to attribute CPU usage to different activities. When you use multiple regions files, different regions of interest can overlap and conflict. When these conflicts occur, WPA is unable to accurately attribute a single activity to a given thread in a given time range.

To avoid these potential conflicts, use only one region definition file at a time.

See Also

Other Resources

Creating a Regions of Interest File
WPA Features

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