Static Probabilistic Timing Analysis for Multi-path Programs

Abstract

This paper introduces an effective Static Probabilistic Timing Analysis (SPTA) for multi-path programs. The analysis estimates the temporal contribution of an evict-on-miss, random replacement cache to the probabilistic Worst-Case Execution Time (pWCET) distribution of multi-path programs. The analysis uses a conservative join function that provides a proper overapproximation of the possible cache contents and the pWCET distribution on path convergence, irrespective of the actual path followed during execution. Simple program transformations are introduced that reduce the impact of path indeterminism while ensuring sound pWCET estimates. Evaluation shows that the proposed method is efficient at capturing locality in the cache, and substantially outperforms the only prior approach to SPTA for multi-path programs based on path merging. The evaluation results show incomparability with analysis for an equivalent deterministic system using an LRU cache.