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

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This topic describes how to use Visual Studio Profiling Tools command-line tools to attach the Profiler to an ASP.NET 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 at a command prompt, 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 Specifying the Path to Profiling Tools Command Line Tools.

Note

Only the /start:concurrency,resourceonly option is supported for Web applications. Collecting thread activity and visualization data by using the /start:concurrency or /start:concurrency,threadonly option is not supported.

To collect concurrency data, you attach the profiler to the ASP.NET worker process that hosts your Web site. 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. In most cases, you should clear the profiling environment variables at the end of a session.

Attaching the Profiler

To attach the Profiler to a ASP.NET application

  1. Start the profiler by typing the following command:

    VSPerfCmd **/start:concurrency,ResourceOnly /output:**OutputFile [Options]

    • The /start option initializes the profiler to collect resource contention data.

    • The /output**:**OutputFile option is required with /start. OutputFile specifies the name and location of the profiling data (.vsp) file.

    You can use any option in the following table with the /start option.

    Option

    Description

    /user:[Domain\]UserName

    Specifies the optional domain and user name of the account to be granted access to the profiler.

    /crosssession

    Enables profiling of processes in other logon sessions.

    /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. The default value is 500.

    /events:Config

    Specifies an Event Tracing for Windows (ETW) event to be collected during profiling. ETW events are collected in a separate (.etl) file.

  2. Start the ASP.NET application in the typical way.

  3. Attach the profiler to the ASP.NET worker process by typing the following command:**VSPerfCmd /attach:PID [/targetclr:**Version]

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

    • /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. This parameter is optional.

Controlling Data Collection

While the application is running, you can control data collection by starting and stopping the writing of data to the file by using VSPerfCmd.exe options. By controlling data collection, you can 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 pairs of VSPerfCmd options in the following table 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 that the process ID (PID) specifies.

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

    /attach starts to collect data for the process that the process ID (PID) or process name (ProcName) specifies. /detach stops data collection for the specified process or for all processes if no process is 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 time stamp, and an optional user-defined text string. Marks can be used to filter the data in profiler reports and data views.

Ending the Profiling Session

To end a profiling session, the profiler must not be collecting data. You can stop collecting data from a application that is profiled with the concurrency method by restarting the ASP.NET worker process or by invoking the VSPerfCmd /detach option. You then invoke the VSPerfCmd /shutdown option to turn off the profiler 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. Detach the profiler from the target application by closing it or by typing the following at a command prompt:

    VSPerfCmd /detach

  2. Shut down the profiler by typing the following command at a command prompt:

    VSPerfCmd /shutdown

See Also

Concepts

Command-Line Profiling of ASP.NET Web Applications

Rapid Web Site Profiling with VSPerfASPNETCmd

Change History

Date

History

Reason

December, 2011

Removed VSPerfClrEnv /sampleon step.

Content bug fix.