It’s possible, using the isolcpus kernel command line argument, to prevent the scheduler from managing certain CPU cores. You can then manually assign a thread

It’s possible, using the isolcpus kernel command line argument, to prevent the scheduler from managing certain CPU cores. You can then manually assign a thread to an isolated core, and it will run there without any interruptions from thread switching. You can also map interrupt handlers away from those isolated CPUs. There may be architectural things that cause interruptions you can’t mitigate though (like SMIs on Intel).