NUVA: Architectural support for runtime verification of parametric specifications over multicores

Runtime Verification (RV) has recently emerged as a complementary technology to extend coverage of conventional software verification methods. To address the substantial performance and power overhead of pure software RV frameworks, this paper introduces NUVA, which stands for nonuniform verification architecture, a distributed automata-based RV architecture for parametric specifications in the form of parameterized finite-state automata, with a case study over a cache-coherent nonuniform-memory-access (ccNUMA) multiprocessor. The core of NUVA is a coherent distributed automata transactional memory (ATM) that efficiently maintains states of a dynamic population of automata checkers organized into a rooted dynamic directed acyclic graph (DAG) concurrently shared among all processor nodes. A cycle-accurate model of a ccNUMA multiprocessor confirms that performance slowdown is 1~3% and NoC message traffic increases by 10~15% at parametric event density¹ of 0.025 EPI for two compute-intensive scientific benchmarks having irregular concurrent data structures. The detailed architecture and implementation metrics in TSMC 40nm CMOS technology are presented. NUVA can be dimensioned to incur average total power overhead of less than 140mW and area overhead of 4mm² for a quad-core multiprocessor chip, at operating frequency of 250MHz. It is also estimated to incur 1.9~2.6% area overhead and 0.5~1% power overhead when integrated with Intel´s family of high-end desktop and mobile quad-core processors operating at 1.6~3.2GHz. Our silicon implementation achieves average performance² of 1.5 MEPS/mW. For a processor core with 5 MIPS/mW, this corresponds to a 3.2% drop in energy efficiency at parametric event density of 0.01 EPI.