How to: Attach the Profiler to a .NET Service to Collect Application Statistics by Using the Command Line

This topic describes how to use Visual Studio Profiling Tools command-line tools to attach the profiler to a .NET Framework service and collect performance statistics by using the sampling method.

To collect performance data from a .NET Framework service, you must use the VSPerfCLREnv.cmd tool to initialize the appropriate environment variables. You must then restart the computer that hosts the service and configure that computer for profiling. You then attach the profiler to the service process. When 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. In most cases, we recommend clearing the profiling environment variables at the end of a session.

Attaching the Profiler

To attach the Profiler to a .NET Framework service

1. Install the service.

2. Open a command prompt window.

3. Initialize the profiling environment variables. Type:

   VSPerfClrEnv /globalsampleon [/samplelineoff]

   • /globalsampleon enables sampling.

   • /samplelineoff disables the assignment of collected data to specific source code lines. When this option is specified, data is assigned only to functions.

4. Restart the computer.

5. Open a command prompt window.

6. 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 service 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.

7. If necessary, start the service.

8. Attach the profiler to the service. Type:

   VSPerfCmd /attach: {PID|ProcName} [Sample Event] [/targetclr**:**Version]

   • Specify the process ID (PID) or process name (ProcName) of the service. You can view the process IDs and names 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 100 samples per second 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.

   • **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.

Controlling Data Collection

When the service 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 specific process is not specified.

Ending the Profiling Session

To end a profiling session, the profiler must be detached from all profiled processes and the profiler must be explicitly shut down . You can detach the from an application profiled with the sampling method by closing the application 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:

   • Stop the service.

     -or-

   • Type VSPerfCmd /detach

2. Shut down the profiler. Type:

   VSPerfCmd /shutdown

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

   VSPerfClrEnv /globaloff

4. Restart the computer.

See Also

Concepts

Command-Line Profiling of Services

Other Resources

Profiler Sampling Method Data Views