How to: Attach the Profiler to an ASP.NET Web Application to Collect Memory Data by Using the Command Line

This topic describes how to use Visual Studio Team System Developer Edition Profiling Tools command-line tools to attach the profiler to a ASP.NET Web application and collect data about the number and size of .NET Framework memory allocations. You can also collect data about the lifetime of .NET Framework memory objects.

To collect performance data from a ASP.NET Web application, you must use the VSPerfCLREnv.cmd  tool to initialize the appropriate environment variables on the computer that hosts the ASP.NET Web application. You must then restart the computer to configure the Web server for profiling.

You then use the VSPerfCmd.exe tool to attach the profiler to the ASP.NET worker process that hosts your Web site. When the profiler is attached to the application, you can pause and resume data collection.

To end a profiling session, the profiler must no longer be attached to the application and the profiler must be explicitly shut down. In most cases, we recommend clearing the profiling environment variables at the end of a session.

To attach the Profiler to an ASP.NET Web application

  1. Open a command prompt window. If necessary, add the profiler tools directory to your PATH environment variable. The path is not added at installation.

    32 bit computers

    On 32 bit computers, the default profiler tools directory is

    \Program Files\Microsoft Visual Studio 9.0\Team Tools\Performance Tools.

    64 bit computers

    On 64 bit computers, specify the path according to the target platform of the application to be profiled.

    To profile 32 bit applications, the default profiler tools directory is

    \Program Files (x86)\Microsoft Visual Studio 9.0\Team Tools\Performance Tools

    To profile 64 bit applications, the default profiler tools directory is

    \Program Files (x86)\Microsoft Visual Studio 9.0\Team Tools\Performance Tools\x64

    For example, to add the profiler directory to PATH on a 32 bit computer, type

    set path=%path%;C:\Program Files\Microsoft Visual Studio 9.0\Team Tools\Performance Tools

  2. Initialize the profiling environment variables. Type:

    VSPerfClrEnv {/globalsamplegc | /globalsamplegclife} [/samplelineoff]

    • The options /globalsamplegclife and /globalsamplegclife specify the type of memory data to collect.

    Specify one and only one of the following options.

    /globalsamplegc

    Enables the collection of memory allocation data.

    /globalsamplegclife

    Enables the collection of both memory allocation data and object lifetime data.

    • The option /samplelineoff disables the assignment of collected data to specific source code lines. If this option is specified, data is assigned at the function level.

  3. Restart the computer to set the new environment configuration.

  4. Open a command prompt window. If necessary, set the profiler path enviroment variable.

  5. Start the profiler. Type:

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

    • The /start:sample 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:sample option.

    NoteNote:

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

    /user:[Domain\]UserName

    Specifies the 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 other than the logged on user. The process owner is listed in the User Name column on the Processes tab of Windows Task Manager.

    /crosssession

    Enables profiling of processes in other logon sessions. This option is required if the ASP.NET 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.

    /waitstart [:Interval]

    Specifies the number of seconds to wait for the profiler to initialize before it returns an error. If Interval is not specified, the profiler waits indefinitely. By default, /start returns immediately.

    /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.

  6. Start the ASP.NET Web application in the typical way.

  7. Attach the profiler to the ASP.NET worker process. Type:

    VSPerfCmd /attach:{PID|ProcName}

    • PID specifies the process ID or the process name of the ASP.NET worker process. You can view the process IDs of all running processes in Windows Task Manager.

While the application is running, you can control data collection by starting and stopping the writing of data to the profiler data 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 VSPerfCmd 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).

    /attach: :{PID|ProcName}/detach[:{PID|:ProcName}]

    /attach starts to collect data for the process specified by the process ID or process name. /detach stops data collection for the specified process, or for all processes if a specific process is not specified.

  • You can also use the VSPerfCmd.exe /mark option to insert a profiling mark into the data file. The /mark command adds an identifier, a timestamp, and an optional user-defined text string. Marks can be used to filter the data in profiler reports and data views.

To end a profiling session, the profiler must be detached from the Web application. You can stop the collection of data from an application profiled with the sampling method by restarting the ASP.NET worker process or by calling the VSPerfCmd /detach option. You then 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, but the system configuration is not reset until the computer is restarted.

To end a profiling session

  1. Do one of the following to detach the profiler from the target application:

    • Type VSPerfCmd /detach

      -or-

    • Close the ASP.NET worker process. Type:

    IISReset /stop

  2. Shut down the profiler. Type:

    VSPerfCmd /shutdown

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

    VSPerfCmd /globaloff

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

    IISReset /start

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