Abstract

We propose and analyze a proportional share resource allocation algorithm for realizing real-time performance in time-shared operating systems. In a proportional share system, processes are assigned a weight which determines a share (percentage) of the resource they are to receive. The resource is then allocated in discrete-sized time quanta in such a manner that each process makes progress at a precise, uniform rate. Proportional share allocation algorithms are of interest because (1) they provide a natural means of seamlessly integrating real- and non-real-time processing requirements in a general purpose operating system, (2) they are easy to implement (and in particular, easier than more traditional forms of real-time support such as periodic tasks), (3) they provide a simple and effective means of precisely controlling the real-time performance of a process including uniform, predictable degradation in times of system overload, and (4) they provide a natural mean of policing proce...

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