Xenomai realtime kernel (amd64)

Choose and copy and paste the following into a shell to install your kernel:

sudo apt-get install linux-image-xenomai.x86-amd64 	  # amd64

RT-PREEMPT realtime kernel (amd64)

There is currently no stock Debian RT-PREEMPT kernel for Jessie. The Debian meta package linux-image-rt-[amd64/i386] will error if you try to install it with an error message similar to

The following packages have unmet dependencies:
 linux-image-rt-amd64 : Depends: linux-image-4.1.0-0.bpo.1-rt-amd64 but it is not installable

The machinekit apt repository provides several known-to work kernels, plus headers etc.

If you install the machinekit-rt-preempt package, one of these will be installed automatically.

Alternately you can build your own kernel (see the developing section for more details) or manually install another kernel.

Choose and copy and paste one of the following into a shell to install your kernel:

sudo apt-get install linux-image-4.1.15-rt17mah     # amd64 and i386

sudo apt-get install linux-image-4.1.19-rt22mah     # amd64 and i386

sudo apt-get install linux-image-4.8.0-1-rt-amd64   # amd64
sudo apt-get install linux-image-4.8.0-1-rt-686-pae # i386