Some applications require guaranteed access to the CPU without even brief
interruptions; realtime systems and high-bandwidth networking applications
with user-space drivers can fall into the category. While Linux provides
some support for CPU isolation (moving everything but the critical task off
of one or more CPUs) now, it is an imperfect solution that is still subject
to some interruptions. Work has been continuing in the community to
improve the kernel’s CPU-isolation capabilities, notably with improvements
in the nohz (tickless) mode, but it is not finished yet. Recently, Alex
Belits submitted
a patch set (based on work by Chris Metcalf
in 2015) that introduces a completely predictable environment for Linux
applications — as long as they do not need any kernel services.

Source: LWN.net – [$] A full task-isolation mode for the kernel