The AUT's memory increases when QTP is running tests against it, compared to manual operations. How can we accurately measure the AUT memmory usage in QTP?
The memory of the AUT is increased the first time the AUT is invoked and QTP begins to execute the test against it.. Eventually the memory stabalizes.
This is due to the QTP agent being injected into the AUT process during run time. It is quite normal that a WPF AUT will use a larger amount of memory with the WPF agent injected.
To measure the AUT's memory usage, you may use the Local System Monitor from the QTP. You may configure it in the File->Settings->Local System Monitor. But using it to measure memory usage of application is not good idea, because memory usage with the QTP running is not the same as plain run of an application.
The Local System Moniotor is only intended to monitor system resource usage of an application under test. So if you need a tool to monitor the memory of the application, use some other tools instead of QTP.
For example, the windows task manager or the Windows Performance Monitor. Generally QTP is not intended for system resource monitoring.