Sharable versus Non-Sharable Real-Time Resources

In [WK94], we define a real-time producers/consumers problem where all tasks are periodic and all resources are non-sharable/non-reusable. In this paper, we study the same problem but with sharable resources. We define a quantitative measure, resource freshness ratio (RFR), to represent the effect of sharable versus non-sharable resources on improving the resource freshness when tasks start simultaneously. We consider the RFR values for both average case freshness (ACF) andworst case freshness (WCF), i.e., RFR 23 and RFR 12 if all <-producer tasks have shorter cycle time than any of the<-consumer tasks, wherem is the amount of < consumed in one hyper-cycle. Both bounds are tight. We also explain why these results are useful in the domain of real-time network monitoring, control, and management. Wu is supported in part by an IBM Fellowship and in part by the NSF Engineering Research Center for Telecommunications Research. yKaiser is supported by National Science Foundation grants CCR-9106368 and CCR-8858029, by grants from AT&T;, BNR, Bull, DEC, IBM, Paramax and SRA, and by the New York State Center for Advanced Technology in Computers and Information Systems.