Summary: Technical Report UIUCDCS­R­98­2068, UILU­ENG­98­1730
Department of Computer Science, University of Illinois at Urbana Champaign, August, 1998.
CPU Service Classes for Multimedia Applications
Hao­hua Chu \Lambda and Klara Nahrstedt \Lambda
Department of Computer Science
University of Illinois at Urbana Champaign
h­chu3,klara@cs.uiuc.edu
Abstract
We present the design, implementation, and experimental results of our soft real time (SRT) system for
multimedia applications in a general purpose UNIX environment. The SRT system supports several service
classes for the real time processes based on their processor usage time pattern: periodic constant processing
time(PCPT) class, aperiodic constant processing time(ACPT) class, variable processing time (VPT) class, and
one­time constant processing time(OCPT) class. It also provides the following features: (1) reservation and timing
guarantees for the service classes, (2) overrun protection among real time processes, (3) dynamic earliest deadline
first (EDF) algorithm for scheduling of multiple real time (RT) processes,(4) overrun scheduling algorithm, (5)
system­initiated adaptation strategies, (6) probing service to estimate the amount of processing time needed prior
to a reservation, (7) profiling service to record and retrieve the processing time needed for a reservation, (8)
synchronization support among concurrent and cooperating real time processes, and (9) guaranteed allocation
for traditional time sharing (TS) processes. Another unique feature of the SRT system is its easy portability to
any operating systems with real time extensions because it is implemented purely in the user space without any

Source: Adve, Sarita - Department of Computer Science, University of Illinois at Urbana-Champaign

Collections: Computer Technologies and Information Sciences