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.
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