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How to: Attach the profiler to a native service to collect application statistics by using the command line (VSPerfCmd)

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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 the Visual Studio Profiling Tools command-line tools to attach the profiler to a native service and collect performance statistics by using the sampling method.

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.

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.

While the profiler is attached to the service, you can pause and resume data collection.

To end a profiling session, the profiler must be detached from the service and the profiler must be explicitly shut down.

Start the application with the profiler

To attach the profiler to a native service, you use the VSPerfCmd.exe/start and /attach options to initialize the profiler and attach it to the target application. You can specify /start and /attach and their respective options on a single command line. You can also add the /globaloff option to pause data collection at the start of the target application. You can then use /globalon to begin collecting data.

To attach the profiler to a native service

  1. If necessary, start the service.

  2. Open a command prompt window.

  3. 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.

    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 profiled process. This option is required only 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 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 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.

  4. Attach the profiler to the service. Type:

    VSPerfCmd /attach: PID [Sample Event]

    PID specifies the process ID of the target application. You can view the process IDs of all running processes in Windows Task Manager.

    By default, performance data is sampled every 10,000,000 non-halted processor clock cycles. This is approximately once every 10 seconds on a 1GH processor. You can specify one of the following options to change the clock cycle interval or to specify a different sampling event.

    Sample Event Description
    /timer : Interval Changes the sampling interval to the number of non-halted clock cycles specified by Interval.
    /pf[:Interval] Changes the sampling event to page faults. If Interval is specified, sets the number of page faults between samples. Default is 10.
    /sys [:Interval] Changes the sampling event to system calls from the process to the operating system kernel (syscalls). If Interval is specified, sets the number of calls between samples. Default is 10.
    /counter : Config Changes the sampling event and interval to the processor performance counter and interval specified in Config.

Control data collection

While the target application is running, you can use VSPerfCmd.exe options to start and stop the writing of data to the profiler data file. 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).
    /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 process is not specified.

End the profiling session

To end a profiling session, the profiler must be detached from the service and then explicitly shut down. You can detach native service that is being profiled with the sampling method by stopping the service 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.

To end a profiling session

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

    • Stop the service.

      -or-

    • Type VSPerfCmd /detach

  2. Shut down the profiler. Type:

    VSPerfCmd /shutdown

See also