Automated analysis and fine-tuning of timing properties in embedded real-time systems

Abstract

An extremely time-consuming task of producing an embedded real-time system is the final analysis and fine-tuning of the system's timing. Existing CASE tools focus on the software specification and design of embedded systems. They provide little, if any, support after the software has been implemented. Even if the developer uses a CASE tool to design their system, it likely does not meet the timing specifications on the first try. This happens because the CASE tool's software design and real-time analysis is based only on estimated data and idealized models. The tools do not take into account practical concerns such as operatin system overhead, interrupt handling, limitations of the programming language or processor, inaccuracies in estimating worst-case execution time of each process, and software errors introduced at the implementation phase by the programmers.Performance monitoring tools allow developers to obtain raw data from the underlying embedded system in real-time. These tools provide most, if not all, of the data needed to pinpoint the problem. Such data, however, is not provided in a symbolic fashion, and thus could be very difficult to understand. The monitors only show what happened during run-time, without correlating those results to the original specifications. Performance monitors also do not perform any analysis on the data that is collected. As a result, there is no means to easily differentiate between parts of the execution that are "normal" versus those parts thathave difficult-to-detect timing errors. Only an expert's eye can quickly spot the differences.We are investigating tools that can help embedded system designers analyze, debug, and fine-tune the timing characteristics of their embedded implementations. Such a tool can have a major impact, by allowing designers whose expertise is in an area other than real-time system analysis, such as communications, controls, or hardware design, to use the tool and obtain valuable information on how to fix their code that is not performing according to specifications.