You should make sure that what you're looking at is very recent; that it is aware of features in the most-recent Linux kernel versions.
And, beyond that ... bear in mind that Linux is not designed to be a true RTOS. The requirements of an RTOS are highly specialized and generally mutually-exclusive with the needs of the general purpose OS. (Most of the time, an RTOS kernel running one CPU is served by Linux running on another "sister" CPU, because the RTOS's attention is necessarily dominated by hard response-time requirements and minuscule time-slices.)
Last edited by sundialsvcs; 11-28-2012 at 12:04 PM.