Reducing the Implementation Overheads of IPCP and DFP

H. Almatary, N. C. Audsley, A. Burns

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


Most resource control protocols such as IPCP (Immediate Priority Ceiling Protocol) require a kernel system call to implement the necessary control over any shared data. This call can be expensive, involving a potentially slow switch from CPU user-mode to kernel-mode (and back). In this paper we look at two anticipatory schemes (IPCP and DFP - Deadline Floor Protocol) and show how they can be implemented with the minimum number of calls on the kernel. Specifically, no kernel calls are needed when there is no contention, and only one when there is. A standard implementation would need two such calls. The protocols developed are verified by the use of model checking. A prototype implementation is described for POSIX pThreads (thus opening up improvements to a range of programming approaches). Experimental results demonstrate the effectiveness of the scheme, showing average case savings of 86%.

Original languageEnglish
Title of host publicationProceedings - Real-Time Systems Symposium
Number of pages10
ISBN (Print)9781467395076
Publication statusPublished - 18 Jan 2016
Event36th IEEE Real-Time Systems Symposium, RTSS 2015 - San Antonio, United States
Duration: 1 Dec 20154 Dec 2015


Conference36th IEEE Real-Time Systems Symposium, RTSS 2015
Country/TerritoryUnited States
CitySan Antonio

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