PIPELINE SYSTEM AND METHOD FOR MULTIPROCESSOR APPLICATIONS IN WHICH EACH OF A PLURALITY OF THREADS EXECUTE ALL STEPS OF A PROCESS CHARACTERIZED BY NORMAL AND PARALLEL STEPS ON A RESPECTIVE DATUM

A pipelined process execution control system for multiprocessors is disclosed that enables multiple processors to cooperatively execute one or many software processes so that cache locality is not violated and extensive state, or context, information need not be saved and restored for each small piece of work performed on multiple data items. The present pipelined process execution control system incorporates (1) a software procedure defined as a pipelined sequence of normal or parallel steps, (2) multiple threads running on the multiprocessor, each of which executes the entire sequence of steps on one datum or data item from a received data stream, and (3) a process control structure to control the threads executing the sequence of steps, so that the normal steps are executed by only one thread at a time and the threads begin executing (or "enter") subsequent normal steps in the sequence in the same order as the threads entered the first step of the sequence. Parallel steps can be executed by more than one thread in parallel. The process control structure provides a process control data structure to track which of the steps is currently being executed by each thread. To eliminate the possibility of simultaneous memory access attempts by the multiple processors hosting the threads, the process control data structure is accessible to only one thread at a time. One specific process control structure disclosed is a mutex combined with a mutex control data structure.