Profiling troubleshooting

• Cannot profile a local application?
• Cannot profile a remote application?
• Check agent status in a web browser
• Enable extended diagnostics in the profiler UI log file

Cannot profile a local application?

• Ensure that the application is started with the profiler and is running when you connect.

  You cannot profile application started without the profiler. The only exception is applications running on .NET Framework 4 or newer, which support attaching of the profiler to an already running process. However, the attach mode has its limitations, thus you may prefer to start application with the profiler instead.

  If the application has not started or unexpectedly terminated, check the application's output and logs for possible errors. Please also check the profiler agent log file <user home>/.ynp/log/<session name>-<PID>.log

• If the application is up and running, ensure that the profiler agent port is not blocked by a firewall, an antivirus etc. Check both the remote machine side and the local machine side. The profiler agent port must be allowed.

  Please note, that agent port is not one of the ports you may use to communicate with the profiled application or server, like HTTP 8080. Instead, it's a special dedicated port used solely by the profiler.

  By default, the profiler agent port is allocated in the range 10001-10010 or a random one is used if all ports in this range are busy. The port can also be specified explicitly with the startup option port. If the profiler agent port is not in the default range 10001-10010, explicitly specify the port in the connect dialog as host:port.

  If you are unsure which port is used, look at the profiler agent log on the remote machine. The profiler agent log file is <user home>/.ynp/log/<session name>-<PID>.log, where <user home> corresponds to the account under which the profiled application is started.

  If you are uncertain about the log file path, you may find it in the profiler agent's output to stderr:

  [YourKit .NET Profiler 2021.11-b123] Log file: <full path to the log file>

• Due to some system settings such as security permissions, enabling profiling may not work for some .NET applications.

  In this case, the application will start, but the profiler agent log file <user home>/.ynp/log/<session name>-<PID>.log will not be created.

  As a workaround, try to enable profiling manually.

• If application to be profiled has started with the profiler, which is shown by the profiler agent log file which has been created (<user home>/.ynp/log/<session name>-<PID>.log), but the Welcome screen does not show the application, please try Profile remote application... action on Welcome screen, specifying "localhost" as host name, and using the port which you should have seen in the profiler agent log.

Cannot profile a remote application?

• Ensure that the application is started with the profiler and is running when you connect.

  If it didn't start or terminated by the moment, check the application's output, logs etc. for possible errors, or restart the application if it was intentionally shut down.

• If the application is up and running, ensure that the network connection is not blocked by a firewall, an antivirus etc.

  Check both the remote machine side and the local machine side.

  The profiler agent port must be allowed.

  The profiler agent port is not the same port as the ports which your profiled application normally uses, such as 8080 etc.

  The default profiler agent port range is 10001-10010. When an application starts with the profiler, the profiler first makes attempt to allocate a free port in this range. Remote profiled applications listening on ports in this range can be automatically detected when you connect.

  If all ports in the range are busy, an arbitrary port is chosen. In this case, you should explicitly specify the host and the port in the connect dialog as host:port You can find the port number on the remote machine in the log file <user home>/.ynp/log/<session name>-<PID>.log

Check agent status in a web browser

If the profiled .NET application is missing in Monitor Applications list, then the profiler agent status can be checked by opening the URL https://localhost:<agent port> for a local profiled application or https://<remote host>:<agent port> for a remote profiled application in a web browser. The remote application status can be checked this way if a direct connection was allowed with the help of the agent startup option listen.

If profiler agent uses self-signed SSL certificate (the default option), then all modern web browsers like Chrome, FireFox or InternetExplorer will show a security warning, explaining the risks. You can safely accept the risks and proceed further.

On the opened page you should see the version of the profiler agent you have connected to. Something like:

YourKit .NET Profiler 2021.11-b123

Enable extended diagnostics in the profiler UI log file

To help YourKit support investigate a network connectivity issue, please enable extended log messages in the profiler UI log file by adding the following line to <user home>/.ynp/ui.ini:

• -Dyk.ssh.debug=true