Mach/4.3BSD: A Conservative Approach to Parallelization

Mach is a new operating system targeted for distributed and multiprocessor environments. Mach contains 4.3BSD compatibility code that, unlike the Mach kernel proper, runs only on a single processor, thus presenting a performance bottleneck to a multiprocessor system. Pieces of the 4.3BSD compatibility code were selectively parallelized to reduce this bottleneck. Signifrcantly improved multiprocessor and multi-user performance was achieved using minimum modifrcation of existing data structures and algorithms. A framework was left in place for future parallelization