Development and Certification of Mixed-Criticality Embedded Systems based on Probabilistic Timing Analysis

• DIRECTORS: Francisco J. Cazorla, Mikel Azkarate-askasua
• UNIVERSITY: Universitat Politècnica de Catalunya (UPC) 

Abstract:

The overall goal of this PhD rests on the development and safety certification of mixed-criticality embedded systems running on multicore devices that integrate MBPTA timing analysis techniques for guaranteeing safe probabilistic WCET bounds. 
This PhD is framed within the FP7-PROXIMA European project, which seeks for an innovative technique for the analysis of the temporal behaviour of mixed-criticality multicore and manycore systems. On this basis, the major contribution of PROXIMA is the Probabilistic Timing Analysis (PTA) (and its measurement-based (MBPTA) variant) technique applied to multi-/manycore platforms. 

The WCET estimation and timing analysis of multicore processors with shared resources is a technical challenge with direct impact on certification. For instance, achieving spatial and temporal independence in mixed-criticality systems is a key requirement stated in most safety standards in the field. While spatial isolation can be commonly addressed using state-of-the-art solutions (e.g., MMU), temporal independence at application level depends on the time guarantees provided by the underlying multicore processor. However, as processor complexity increases, so do the sources and effects of temporal interferences, and consequently, determinism and predictability are conspicuous by their absence in modern multicore platforms that are designed to offer maximum average performance at the cost of increasing complexity. 

A common design principle to deal with those uncertainties rests on adding conservative safety margins to the WCET value, resulting in an ineffective use of the available resources. MBPTA may aid in preventing this resource over-provisioning but in turn it requires adopting a MBPTA-friendly processor design. 

This PhD is directed towards the development and certification of mixed-criticality multicore solutions that use MBPTA for asserting safe timing guarantees. To this end, the impact that MBPTA-compliant design principles have on system’s safety has to be analysed and new safety measures applied in accordance to current safety standards.