PREEMPT — Preemptible kernel (low-latency desktop)
This option reduces the latency of the kernel by making
all kernel code (except code executing in a critical section)
preemptible. This allows reaction to interactive events by
permitting a low priority process to be preempted involuntarily
even if it is in kernel mode executing a system call and would
otherwise not be about to reach a natural preemption point.
This allows applications to appear to run more smoothly even when the
system is under load, at the cost of slighly lower throughput
and a slight runtime overhead to kernel code.
Select this if you are building a kernel for a desktop or
embedded system with latency requirements in the milliseconds