Advanced Laboratory on Embedded Systems S.r.l.

Randomized HW/SW Architectures Move towards a truly randomized architectures— Opposite direction of predictable (deterministic) HW/SW architectures— Break any dependency on code execution history (typical in caches, butnot only there!)— Probabilistic analysis suffers dependencies (i.e. it is much simpler to relyon statistical independence) Example with caches:— Randomized replacement policy (select random a replacement victim)— Traditional replacement (LRU) depends on execution history• probabilistic execution time analysis suffer of systemic cache misses (probabilisticanalysis relies on statistical independence) Problems/Doubts— How to achieve true randomization ?— Is this still cost effective ?— A reduced complexity architecture could achieve better meanperformance and B/WCET bounds ?[ecrts09.pdf “Using Randomized Caches in Probabilistic Real-Time Systems”]7/9/2012 [ACM-probabilistic_rt.pdf Alberto “PROARTIS: Ferrari - ALES S.r.l. Probabilistically Analysable Real-Time Systems”] 22