12. 12. 2014

MC-IPC: A Synchronous IPC Protocol with Strict Bandwidth Isolation Guarantees for Mixed-Criticality Multiprocessor Real-Time Systems


Björn B. Brandenburg

MPI SWS


In mixed-criticality real-time systems, tasks of different criticality (i.e., of different "importance" and subject to varying levels of trust) are hosted on a shared hardware platform. In such a setup, highly critical tasks must be temporally and logically isolated from faults in (untrusted) lower-criticality tasks. To ensure the required logical isolation, it is natural to encapsulate shared resources (such as shared data structures, OS services, access to I/O ports, etc.) in resource servers (in the microkernel sense) that are accessed via IPC. To provide the required temporal isolation, the shared resource servers must be accessed with a real-time-aware IPC protocol. This talk will present MC-IPC, the first such protocol for sharing single-threaded resource servers on multiprocessors among mutually untrusted clients of differing criticality. Assuming reservation-based scheduling, the MC-IPC protocol ensures strict bandwidth isolation by leveraging and extending recent advances in suspension-oblivious multiprocessor real-time locking. In this talk, I will introduce the protocol, explain how the isolation guarantees are derived from an unusual three-level, multi-ended hybrid FIFO-FIFO-priority queue, and present empirical results from a case study investigating several antagonistic failure modes based on an implementation in LITMUS^RT.
28. Oct 2020
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