User-level interprocess communication for shared memory multiprocessors

this paper, provides safe and efficient communication between address spaces on the same machine without kernel mediation. URPC isolates from one other the three components of interprocess communication: processor reallocation, thread management, and data transfer. Control transfer between address spaces, which is the communication abstraction presented to the programmer, is implemented through a combination of thread management and processor reallocation. Only processor reallocation requires kernel volvement; thread management and data transfer do not. Thread management and interprocess communication are done by application~level libraries, rather than by the kernel