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Real-time systems need time-predictable computing platforms. For a multicore processor to be time-predictable, communication between processor cores needs to be time-predictable as well. This paper presents a time-predictable message-passing library for such a platform. We show how to build up abstraction layers from a simple, time-division multiplexed hardware push channel. We develop these time-predictable abstractions and implement them in software. To prove the time-predictability of these functions we analyze their worst-case execution time (WCET) with the aiT WCET analysis tool. We combine these WCET numbers with the calculation of the network latency of a message and then provide a statically computed end-to-end latency for this core-to-core message.

This paper describes an end-to-end framework for the design and the implementation of real-time systems on a many-core architecture. The system, described in the multi-rate synchronous language Prelude, is translated into a set of communicating periodic tasks. We present a first heuristic to compute a partitioning of this task set that takes into account the specifics of the underlying platform, the Intel Single-chip Cloud Computer (SCC). In particular, the heuristic considers the communication between tasks. Furthermore, we provide a schedulability analysis that is used to validate the partitioning. We successfully apply the heuristic to several realistic use cases to evaluate the effectiveness of the proposed framework. For executing the task set, we have developed a run-time environment based on a bare-metal library that allows partitioned non-preemptive earliest deadline first (EDF) scheduling and manages the communication between tasks via the message passing mechanisms provided by the Intel SCC. The evaluation shows that the run-time overheads introduced by the framework are reasonably low.

Following the successful WCET Tool Challenges in 2006 and 2008, the third event in this series was organized in 2011, again with support from the ARTIST DESIGN Network of Excellence. Following the practice established in the previous Challenges, the WCET Tool Challenge 2011 (WCC'11) defined two kinds of problems to be solved by the Challenge participants with their tools, WCET problems, which ask for bounds on the execution time, and flow-analysis problems, which ask for bounds on the number of times certain parts of the code can be executed. The benchmarks to be used in WCC'11 were debie1, PapaBench, and an industrial-strength application from the automotive domain provided by Daimler. Two default execution platforms were suggested to the participants, the ARM7 as "simple target" and the MPC5553/5554 as a "complex target," but participants were free to use other platforms as well. Ten tools participated in WCC'11: aiT, Astrée, Bound-T, FORTAS, METAMOC, OTAWA, SWEET, TimeWeaver, TuBound and WCA.