NB! This article covers only .NET Rider process. For Java process (JetBrains Rider) related issues refer to this article.

MacOS and Linux:

In case you see that Rider slows down on your Mac, and/or dotnet CPU usage spikes up to 100%, please take the following steps:

1. Call the action "Help | Diagnostic tools | Profile Backend with Sampling".
2. Wait until Attaching to profiler process finishes (a progress bar in the bottom status bar will indicate about it and you will see that Profiling is in progress).
3. Perform the actions leading to high CPU usage.
4. Wait for a minute and then stop profiling with the action "Help | Diagnostic tools | Backend: stop profiling".
5. In the bottom right corner you will see a notification popup that a snapshot has been captured and a link to the snapshot file. Collect this snapshot.
6. Create a new issue in the Rider issue tracker. In the issue, provide a short description of the performance problems you're experiencing, share the collected snapshot via uploads.jetbrains.com service, and let us know the exact ID of your upload.

Windows:

Embedded profiler

1. Start Rider;
2. Call "Help -> Diagnostic Tools -> Profile Backend with Timeline | Sampling or Capture Backend Memory Snapshot" if your Rider version is 2020.1+ and Tools -> Backend Profiling -> Start Sampling | Timeline or Dump Memory  if you use Rider2019.3 and older version;
3. Wait until you see "Profiling in progress: stop it manually" message at the bottom; 
4. Perform actions which are slow in Rider (typing, switching between documents, building, etc.);
5. To stop profiling, call "Diagnostic Tools -> Backend: Stop Profiling";
6. At the bottom-right corner, you will get a popup with a performance snapshot file name and "Show in Explorer" link to open a folder;
7. Share the file with us, some ways are mentioned here; 
8. Create a new issue in the Rider issue tracker. In the issue, provide a short description of the performance problems you're experiencing, and specify the name of your snapshot.

Standalone JetBrains dotTrace profiler

These steps are applicable for Windows and MacOS.

1. Download and install JetBrains dotTrace. If you don’t have a suitable license, you can use the 30-day free trial.
2. After launching dotTrace, go to the Profiling tab and click + in Choose what you want to profile section. Then, select .NET Process in the New Run Configuration dialog and click Next. Keep the default configuration and click Save. 

3. In the Choose how you want to profile it section, be sure to select the correct Profiling Type: Timeline is the default, but you can also select Sampling or Tracing if you’ve been asked to collect a sampling or tracing snapshot. 

To learn about the difference between the profiling types, refer to the dotTrace documentation here.

4. If there’s a performance problem during Rider’s startup phase, tick the Collect profiling data from start checkbox.

Make sure to enable this feature if you get a Rider error report during startup, 

for example if Rider crashes or lags before the Welcome dialog appears or you see a critical error message before opening any project in Rider.

5. Run Rider

Performance issues during startup:

• Once Rider starts, open your solution.
• Wait for the solution to finish loading and for Rider to load all of the caches, ensuring the problem is reproduced.
• Click the Get Snapshot and Wait button in the profiling controller window.

Performance issues in other scenarios:

• Once the Rider starts, open your solution.
• Click the Start button in the profiling controller window when you’re ready to reproduce the problem.
• Perform the actions that lead to the performance issue in Rider, such as typing, switching between documents, and building projects.
• Once the relevant actions have been completed, click the Get Snapshot and Wait button in the profiling controller window.

6. The trace will be opened in the dotTrace viewer automatically. If you would like to create a new snapshot without saving the current one, click Drop in the profiling controller window.
7. In the dotTrace Viewer, click File | Save Snapshot… in the toolbar and save the resulting snapshot.
8. Compress (zip) the snapshot file.
9. Use the JetBrains Upload Service to upload the zip package and save the upload ID.
10. You can also create a new support ticket or submit a support request via Help | Contact Support in Rider.  

In the issue, briefly describe the performance problems you're experiencing, making sure to provide your upload ID. If you already have a corresponding support ticket, please send the upload ID to the relevant support engineer.