Is that a CPU scheduler issue though? Linux traditionally has a problem of overall system architecture in that userspace isn't set up to provide policy informa

Is that a CPU scheduler issue though? Linux traditionally has a problem of overall system architecture in that userspace isn't set up to provide policy information such as "this thread is doing UI" vs. "this is a background task" by default. However, if I help the scheduler along by nice(1)-ing my big compute tasks, then the desktop remains perfectly smooth even while the CPU is 100% busy. It'd be much better to have this experience by default, but unfortunately it requires architectural improvements throughout the entire software stack. Trying to band-aid it in the kernel scheduler may allow you to heuristically improve some workloads, but it's ultimately a fool's errand. Where the desktop does tend to fall over and become totally unusable is when the system starts to swap...