How to: Instrument a .NET Framework service and collect memory data by using the profiler command line

  • Article

Applies to: yesVisual Studio noVisual Studio for Mac

Note

This article applies to Visual Studio 2017. If you're looking for the latest Visual Studio documentation, see Visual Studio documentation. We recommend upgrading to the latest version of Visual Studio. Download it here

This article describes how to use Visual Studio Profiling Tools command-line tools to instrument a .NET Framework service and collect memory usage data. You can collect memory allocation data, or you can collect both memory allocation and object lifetime data.

Note

Enhanced security features in Windows 8 and Windows Server 2012 required significant changes in the way the Visual Studio profiler collects data on these platforms. UWP apps also require new collection techniques. See Performance Tools on Windows 8 and Windows Server 2012 applications.

Note

You cannot profile a service with the instrumentation method if the service cannot be restarted after the computer starts, such a service that start when the operating system starts.

To get the path to the profiling tools, see Specify the path to command line tools. 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 the command itself.

Start the profiling session

To collect performance data from a .NET Framework service, you use the VSPerfCLREnv.cmd tool to initialize the appropriate environment variables and the VSInstr.exe tool to create an instrumented copy of the service binary file.

The computer that hosts the service must be restarted to configure it for profiling. You must also start the service manually from the Service Control Manager. You then start the profiler, and then start the .NET Framework service.

When the instrumented component is executed, memory 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 service and explicitly shut down the profiler. In most cases, we recommend clearing the profiling environment variables at the end of a session.

To begin profiling a .NET Framework service

  1. Open a command prompt window.

  2. Use the VSInstr tool to generate an instrumented version of the service binary.

  3. Use Service Control Manager to replace the original binary with the instrumented version. Make sure that the service Startup Type is set to Manual.

  4. Initialize the profiling environment variables. Type:

    VSPerfClrEnv {/globaltracegc | /globaltracegclife}

    • /globaltracegc and /globaltracegclife enable the collection of memory allocation and object lifetime data.

      Option Description
      /globaltracegc Collects memory allocation data only.
      /globaltracegclife Collects memory allocation and object lifetime data.

  5. Restart the computer.

  6. Open a command prompt window.

  7. Start the profiler. Type:

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

    • The /start: contention 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.

    Note

    The /user and /crosssession options are usually required for services.

    Option Description
    /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 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.
    /globaloff To start the profiler with data collection paused, add the /globaloff option to the /start command line. Use /globalon to resume profiling.
    /counter : Config Collects information from the processor performance counter specified in Config. Counter information is added to the data collected at each profiling event.
    /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.

  8. If necessary, start the service.

  9. Attach the profiler to the service. Type:

    VSPerfCmd /attach: PID|ProcessName

    • Specify the process ID or process name of the service. You can view the process IDs and names of all running processes in Windows Task Manager.

Control data collection

While the service is running, you can control data collection by starting and stopping the writing of data to the file with 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.

    Option Description
    /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).

End the profiling session

To end a profiling session, close the application that is running the instrumented component, then start the VSPerfCmd /shutdown option to turn the profiler off and close the profiling data file. The VSPerfClrEnv /globaloff command clears the profiling environment variables.

To end a profiling session

  1. Stop the service from Service Control Manager.

  2. Shut down the profiler. Type:

    VSPerfCmd /shutdown

  3. When you have completed all profiling, clear the profiling environment variables. Type:

    VSPerfClrEnv /globaloff

    Replace the instrumented module with the original. If necessary, reconfigure the Startup Type of the service.

  4. Restart the computer.

See also