KTK: kernel support for configurable objects and invocations

The Kernel Tool Kit (KTK) is an object-based operating system kernel and parallel programming library that ooers explicit support for on-and oo-line program conngu-ration. Speciically, KTK allows the speciication of attributes for object classes, object instances, state variables, operations and object invocations. Attributes are interpreted by policy classes that may be varied separately from the abstractions with which they are associated. They can be used to vary object internal implementation and semantics without aaecting the methods being invoked. In this paper, the runtime connguration of KTK attributes is shown to improve the runtime performance of multiprocessor applications. KTK is layered on a portable and conngurable parallel programming substrate, a Mach Cthreads compatible runtime library .