Program becomes laggy when some cores of the CPU is occupied by other programs.

[OppositeNor]

I am running a program in the background which takes a lot of CPU resources, and I limited the program to run only in some cores on my PC to avoid it from effecting other programs to run. However, in DrRacket every time when I click save after I make some changes it will stuck there and have no respond for a while.
The system I am using is Windows 11, and my CPU has 20 logic processors, and the program I'm running is running on 8 of them. I think this might be caused by the problem with multi-tasking while some of the threads might be stuck in the cores that are occupied, and it influenced the main thread and all other threads from working.

[rfindler]

One thing DrRacket is doing is expanding the program after each edit. That might be what you're seeing. If you click on the little circle in the bottom right corner of the window (usually it is green but it can be other colors sometimes) you can disable it. Does that help?

[OppositeNor]

I disabled it but it's still laggy. I also found out that switching view to another file will also cause it to stuck. The CPU usage is 60%, which has 8 out of 20 processors running at 100%.

[rfindler]

If you start DrRacket from the command line (under windows using racket -l drracket) and then, when it gets stuck, hit control-c, we might be able to get a clue about what's it is trying to do and see a way to speed that up.