PRIORITY-DRIVEN, PREEMPTIVE I/O CONTROLLERS FOR REAL-TIME SYSTEMS.

Brinkley Sprunt, David Kirk, Lui Sha

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The effect of three I/O controller architectures on schedulable utilization, which is the highest attainable resource utilization at or below which all deadlines can be guaranteed, is examined. FIFO (first-in-first-out) request queuing, priority queuing, and priority queuing with preemptable service are simulated for a range of CPU computation to I/O traffic ratios. The results show that, for I/O-bound task sets and zero preemption costs, priority queuing with preemptable service can provide a level of schedulable utilization 35% higher than that attainable with FIFO queuing, and 20% higher than priority queuing and nonpreemptable service. Although the potential gain for priority queuing with preemptable service is large, further simulations that incorporate a time penalty for each preemption show that the gain is very sensitive to preemption cost. With preemption cost represented as a ratio of preemption time to the minimum-task period, the level of schedulable utilization for priority queuing with preemptable service degrades to that of priority queuing with nonpre-emptable service, for a preemption cost ratio of 0. 04. A high-level design of a preemptable I/O controller is described and the issues determining preemption cost are detailed, along with techniques for its minimization.

Original languageEnglish (US)
Title of host publicationUnknown Host Publication Title
PublisherIEEE
Pages152-159
Number of pages8
ISBN (Print)0818608617
StatePublished - Jan 1 1988
Externally publishedYes

ASJC Scopus subject areas

  • Engineering(all)

Fingerprint Dive into the research topics of 'PRIORITY-DRIVEN, PREEMPTIVE I/O CONTROLLERS FOR REAL-TIME SYSTEMS.'. Together they form a unique fingerprint.

Cite this