Cristian Maxim

PROXIMA: Improving Measurement-Based Timing Analysis through Randomisation and Probabilistic Analysis

The use of increasingly complex hardware and software platforms in response to the ever rising performance demands of modern real-time systems complicates the verification and validation of their timing behaviour, which form a time-and-effort-intensive step of system qualification or certification. In this paper we relate the current state of practice in measurement-based timing analysis, the predominant choice for industrial developers, to the proceedings of the PROXIMA (Probabilistic real-time control of mixed-criticality multicore systems) project in that very field. We recall the difficulties that the shift towards more complex computing platforms causes in that regard. Then we discuss the probabilistic approach proposed by PROXIMA to overcome some of those limitations. We present the main principles behind the PROXIMA approach as well as the changes it requires at hardware or software level underneath the application. We also present the current status of the project against its overall goals, and highlight some of the principal confidence-building results achieved so far.

Reproducibility and representativity: mandatory properties for the compositionality of measurement-based WCET estimation approaches

The increased number of systems consisting of multiple interacting components imposes the evolution of timing analyses towards methods able to estimate the timing behavior of an entire system by aggregating timings bounds of its components. In this paper we propose the first discussion on the properties required by measurement-based timing analyses to ensure such compositionality. We identify the properties of reproducibility and representativity as necessary conditions to ensure the convergence of any measurement protocol allowing a compositional measurement-based timing analysis.