On Thu, Jan 05, 2017 at 10:29:57AM +0100, Federico Reghenzani wrote:

Hi all,

Hello-

I'm trying to setup a RT Linux system (currently on 4.8.2 PREEMPT_RT
patched), and I enabled he NO_HZ_FULL flag in order to reduce the
scheduling interrupts jitter. Trying to isolate one core, I also moved
all interrupts and threads to other CPUs.

This works fine, however when I run my RT application, the thread
kimersoftd is always in "running" state, thus the scheduling interrupt
triggers (because there exists more than 1 task available to run).
Consequently, the advantages of NO_HZ_FULL are vanished.

This sounds like the same problem that Haris (cc'd) has looked into and
has put together a proposed solution.  See the thread here:

   http://www.spinics.net/lists/linux-rt-users/msg16113.html

   Julia