We have a HP Proliant DL980 g7 (4x 6core CPUs) server running SLES 11 SP2 + SLERT. The OS is configured to use CPU sets, the first 4 cores reserved for the OS, and the application running in the remaining 20 cores.
If we have an application running with real-time priority, it is possible for the application to cause the server to stop responding. We can still 'ping' the server but it is not possible to interact with the server via the console and it is not possible to SSH into the machine.
My impression was that separating the application on to different CPUs than the OS would prevent an application from hindering the OS.