An Empirical Study on the Adequacy of MBPTA for Tasks Executed on a Complex Computer Architecture with Linux

In order to support the computational demand of Real-Time Systems' (RTSs`) applications, the use of complex hardware will be fundamental. This fact makes analysis of software to derive Worst-Case Execution Time (WCET) an increasingly harder challenge. State-of-the-art WCET analysis techniques are hampered by the ever-growing cost and complexity of obtaining accurate knowledge of the internal operation of advanced processors, and by difficulties in reliably associating variable execution times with tasks' worst-case behaviour through measurement-based techniques. In this work, we performed an empirical assessment of the adequacy of Measurement-Based Probabilistic Timing Analysis (MBPTA) to estimate the pWCET - through Extreme Value Theory (EVT) - of a task executed on a complex computer architecture with Linux. The proposed evaluation has the objective of detecting whether EVT can be deemed suitable for determining pWCET estimates for tasks executed on complex computers.

I. Introduction

As the use of computational systems proliferates in our society, systems with real-time requirements, i.e. Real-Time Systems (RTSs), become ever more common. It is necessary for the RTSs' industry to provide effective, reliable and flexible systems, making them available to the market as quickly as possible. This results in increasing software complexity, where we have more and more equipment with computers controlling and making decisions that affect the physical world and, consequently, that must use complex hardware elements (e.g., cache memories, pipelines, and branch prediction mechanisms). Moreover, such systems comprise today industrial equipment with millions of lines of code and even Linux-based embedded controllers. Consequently, providing guarantees that the temporal requirements are met becomes increasingly difficult [1], [2].