rsession CPU usage when idle

Question

I have recently noticed an issue with my R / RStudio installation. When I have RStudio opened, the CPU usage in activity monitor shows the rsession and kernel_task processe

Answer 1

If you are working in a specific Rstudio project, and this project has lots of files (hundreds or thousands) Rstudio may be trying to index the files -

I fixed this by:

1. From the Rstudio IDE while in a project,
2. Go to Tools -> Project Options
3. Now click on code editing
4. deselect Index R Source Files
5. close everything and restart Rstudio

Editing

Index R source files — Determines whether R source files within the project directory are indexed for code navigation (i.e. go to file/function, go to function definition). Normally this should remain enabled, however if you have a project directory with thousands of files and are concerned about the overhead of monitoring and indexing them you can disable indexing here.
Insert spaces for tab — Determine whether the tab key inserts multiple spaces rather than a tab character (soft tabs). Configure the number of spaces per soft-tab.
Text encoding — Specify the default text encoding for source files. Note that source files which don't match the default encoding can still be opened correctly using the File : Reopen with Encoding menu command. Source