The interference on shared resources caused by concurrently executing applications unpredictably prolongs their execution. Hence, determination of the Worst Case Execution Time (Wcet) of applications executing on shared memory multi-core processors is hard to estimate. This hinders the adoption of Commercial Off The Shelf (Cots) multicore processors in hard real-time systems. The existing techniques opt for tailored multi-core architectures to provide high computation power at predictable execution time. However, this approach yields poor resource utilization and high costs. In this paper, we present a technique to measure the Wcet of applications on multi-core architectures using existing measurement based timing analysis tools. Our technique has a minor area impact (≈ 5%). However, this impact is limited to the emulation devices only and production chips remain unchanged. Thus, our technique does not impact performance of the Cots chips by any ways. The technique is demonstrated by measuring Wcet of benchmark applications using the RapiTime timing analysis tool. The tests are conducted on a quad-core NIOS II processor on an Altera Fpga.
This tutorial explores some of the challenges of measuring performance and timing behaviour of reliable embedded systems and explains techniques and strategies for optimization of reliable software. The tutorial explains and compares different techniques for measurement and analysis of software on embedded targets including tracing methods, in-memory analysis and using hardware support. It shows how those techniques can be used for verification of non-functional properties on-target, including in the context of DO178B/C and the new ISO26262 standard to meet the requirements for safety in automobiles. The tutorial presents optimization at a high and low level, looking at strategies and the tradeoffs that occur in reliable software development, introducing a process that helps to ensure that optimization can have the maximum benefit for the minimum effort.
It is becoming widely accepted that along with the formal specification of functional properties it is necessary, in some systems, to provide a specification of timeliness properties. Unfortunately, the main methods which would seem to provide this form of requirement appear to be targeted at specifying communication protocols. While it is possible to adapt these methods for simple timeliness properties, their use for describing constraints on distributed systems would be impractical This paper introduces a set of definitions for the Z specification language which enables timeliness properties to be represented formally. The toolkit provides a method of framing the temporal specifications, which enables these specifications to be looked at from multiple viewpoints, a feature which facilitates the specification of distributed systems. A formal basis for the toolkit is given, together with justification for the features of the model of time that has been adopted.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.