I wrote a mini OS for a realtime MSP430 application about 10 years ago. It included a non-preemptive multi-tasking scheduler with design limits to ensure that

I wrote a mini OS for a realtime MSP430 application about 10 years ago. It included a non-preemptive multi-tasking scheduler with design limits to ensure that any task was completed within one millisecond. My timer frequency was 20kHz. This was on a single-core micro-controller clocked at 25MHz, that required two clock cycles per instruction. Most anything running Linux today, or even for the past few decades, is faster than my puny MSP430 was, so it makes sense to increase the Linux timer frequency from 250Hz.