lock:used by kernelsemaphore:used by kernelkernel:multiprocessor useTwo or more CPUs, executing on behalf of different processes, can enter the IRIX kernel simultaneously. The kernel is written to optimize concurrent use. It uses semaphores and locks to serialize the use of the data structures that can be used by two or more processes at the same time.
A real-time program may need to use two or more CPUs concurrently in order to finish the work it needs to do in each frame interval. You can structure your real-time program as multiple processes. You can cause these processes to run concurrently on multiple CPUs, and you can use semaphores and locks to protect their common resources. Process creation is discussed later in this chapter, under "Process Management".