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How to: Instrument a Statically Compiled ASP.NET Web Application and Collect Memory Data by Using the Profiler Command Line

This topic describes how to use Visual Studio Profiling Tools command-line tools to instrument a pre-compiled ASP.NET Web component or Web site and collect .NET memory allocation, object lifetime, and detailed timing data.

Note Note

Command-line tools of the Profiling Tools are located in the \Team Tools\Performance Tools subdirectory of the Visual Studio installation directory. On 64 bit computers, both 64 bit and 32 bit versions of the tools are available. To use the profiler command-line tools, you must add the tools path to the PATH environment variable of the command prompt window or add it to to the command itself. For more information, see Specifying the Path to Profiling Tools Command Line Tools.

To collect data from a ASP.NET Web component by using the instrumentation method, you use the VSInstr.exe tool to generate an instrumented version of the component. On the computer that hosts the component, you replace the non-instrumented version of the component with the instrumented version. You then use the VSPerfCLREnv.cmd tool to initialize the global profiling environment variables and restart the host computer. You then start the profiler.

When the instrumented component is executed, timing data is automatically collected to a data file. You can pause and resume data collection during the profiling session.

To end a profiling session, you close the ASP.NET worker process that hosts the component and then explicitly shut down the profiler. In most cases, we recommend clearing the profiling environment variables at the end of a session.

To instrument an ASP.NET Web component and start profiling

  1. Use the VSInstr tool to generate an instrumented version of the target application. If necessary, replace the application binaries on the ASP.NET host computer with the instrumented binaries.

  2. Open a command prompt window

  3. Initialize the .NET profiling environment variables. In a command prompt window, type:

    VSPerfClrEnv /globaltracegc


    VSPerfClrEnv /globaltracegclife

    • /globaltracegc collects .NET memory allocation and timing data.

    • /globaltracegclife collects .NET memory allocation, object lifetime, and detailed timing data.

  4. Restart the computer.

  5. Open a command prompt window.

  6. Start the profiler. In a command prompt window, type:

    VSPerfCmd /start:trace /output:OutputFile [Options]

    • The /start:trace option initializes the profiler.

    • The /output:OutputFile option is required with /start. OutputFile specifies the name and location of the profiling data (.vsp) file.

    You can use any of the following options with the /start:trace option.

    Note Note

    The /user and /crosssession options are usually required for ASP.NET applications.



    /user :[Domain\]UserName

    Specifies the optional domain and user name of the account that owns the ASP.NET worker process. This option is required if the process is running as a user that is different than the logged on user.The name is listed in the User Name column on the Processes tab of Windows Task Manager.


    Enables profiling of processes in other sessions. This option is required if the application is running in a different session. The session id is listed in the Session ID column on the the Processes tab of Windows Task Manager. /CS can be specified as an abbreviation for /crosssession.

    /wincounter : WinCounterPath

    Specifies a Windows performance counter to be collected during profiling.

    /automark : Interval

    Use with /wincounter only. Specifies the number of milliseconds between Windows performance counter collection events. Default is 500 ms.

    /events : Config

    Specifies an Event Tracing for Windows (ETW) event to be collected during profiling. ETW events are collected in a separate (.etl) file.


    To start the profiler with data collection paused, add the /globaloff option to the /start command line. Use /globalon to resume profiling.

  7. Open the Web site that contains the instrumented component.

While the target application is running, you can control data collection by starting and stopping the writing of data to the file by using VSPerfCmd.exe options. Controlling data collection enables you to collect data for a specific part of program execution, such as starting or shutting down the application.

To start and stop data collection

  • The following pairs of options start and stop data collection. Specify each option on a separate command line. You can turn data collection on and off multiple times.



    /globalon /globaloff

    Starts (/globalon) or stops (/globaloff) data collection for all processes.

    /processon : PID /processoff:PID

    Starts (/processon) or stops (/processoff) data collection for the process specified by the process ID (PID).

    /threadon : TID /threadoff:TID

    Starts (/threadon) or stops (/threadoff) data collection for the thread specified by the thread ID (TID).

To end a profiling session, close the ASP.NET Web application, and then use the Internet Information Services (IIS) IISReset command to close the ASP.NET worker process. Call the VSPerfCmd /shutdown option to turn the profiler off and close the profiling data file. The VSPerfClrEnv /globaloff command clears the profiling environment variables. You must restart the computer for the new environment settings to be applied.

To end a profiling session

  1. Close the ASP.NET Web application.

  2. Close the ASP.NET worker process. Type:

    IISReset /stop

  3. Shut down the profiler. Type:

    VSPerfCmd /shutdown

  4. (Optional). Clear the profiling environment variables. Type:

    VSPerfCmd /globaloff

  5. Restart the computer. If necessary, restart IIS. Type:

    IISReset /start