Supporting Read/Write Applications in Embedded Real-time Systems via Suspension-aware Analysis∗

In many embedded real-time systems, applications often in-teract with I/O devices via read/write operations, which may incur considerable suspension delays. Unfortunately, prior analysis methods for validating timing correctness in embedded systems become quite pessimistic when suspen-sion delays are present. In this paper, we consider the prob-lem of supporting two common types of I/O applications in a multiprocessor system, that is, write-only applications and read-write applications. For the write-only applica-tion model, we present a much improved analysis technique that results in only O(m) suspension-related utilization loss, where m is the number of processors. For the second appli-cation model, we present a flexible I/O placement strategy and a corresponding new scheduling algorithm, which can completely circumvent the negative impact due to read- and write-induced suspension delays. We illustrate the feasibil-ity of the proposed I/O-placement-based schedule via a case study implementation. Furthermore, experiments presented herein show that the improvement with respect to system utilization over prior methods is often significant