Do I need to recompile my applications to get realtime performance?
Recompile is not necessary. Userland does not notice any difference if it is running on RT or not, except for a much better RT-responsiveness, only changing the kernel is enough. But, usually, locking bugs in userland applications become much more visible due the more dynamic and fine grained scheduling of the kernel. These are not new bugs, but bugs already existing in the applications, which only become visible on RT (Notice that these bugs are also likely to occur on SMP systems). Also: • A bad designed application on non-RT will never behave realtime on RT. See also HOWTO: Build an RT-application. • Never protect shared/global data in userland processes with semaphores (yes, many people do that…), but use PTHREAD_PRIO_INHERIT mutexes instead. (PTHREAD_PRIO_INHERIT mutexes are only supported in Glibc 2.5 and higher.
