How to: Attach the profiler to a .NET Framework stand-alone application to collect concurrency data by using the command line

This article describes how to use Visual Studio Profiling Tools command-line tools to attach the profiler to a running .NET Framework stand-alone (client) application and collect process and thread concurrency data.


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 the command itself. For more information, see Specify the path to command-line tools.

While 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.

Attach the profiler

To attach the profiler to a running .NET Framework application

  1. Open a command prompt window.

  2. Start the profiler. Type:

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

    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:concurrency option.

    Option Description
    /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.
  3. Start the target application in the typical way.

  4. Attach the profiler to the target application. Type:

    VSPerfCmd /attach: PID [/lineoff] [/targetclr:Version]

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

    • /lineoff disables the collection of line number data.

    • /targetclr : Version specifies the version of the common language runtime (CLR) to profile when more than one version of the runtime is loaded in an application. Optional.

Control data collection

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 the starting or shutting down of the application.

To start and stop data collection

  • The following pairs of VSPerfCmd.exe 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 (PID) or process name (ProcName). /detach stops data collection for the specified process or for all processes if a specific process is not specified.

End the profiling session

To end a profiling session, the profiler must not be collecting data. You can stop collecting data from a application profiled with the concurrency method by closing the application or by invoking the VSPerfCmd /detach option. You then invoke the VSPerfCmd /shutdown option to turn the profiler off and close the profiling data file. The VSPerfClrEnv /off command clears the profiling environment variables.

To end a profiling session

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

    • Type VSPerfCmd /detach


    • Close the target application.

  2. Shut down the profiler. Type: