The "real time" kernel patches are included in Igor's Armbian build tools, but are disabled by default.
Enabling them are simple. (Thanks Igor)
Build "real time" kernel images by doing the following:
apt-get -y install git
git clone https://github.com/igorpecovnik/lib--depth 1
cp lib/compile.sh .
mv ./lib/patch/kernel/sun7i-default/0014-patch-3.4.108-rt136.patch.disabled ./lib/patch/kernel/sun7i-default/0014-patch-3.4.108-rt136.patch
Press "Enter" to continue
Confirm you are running a RT kernel by checking "uname -a" output for PREEMPT
tar xvfz rt-tests-1.0.tar.gz
sudo ./cyclictest -p 80 -t5 -n
Your feedback on tests are welcomed