Analysis of Probabilistic Cache Related Pre-emption Delays

Abstract

This paper integrates analysis of probabilistic cache related pre-emption delays (pCRPD) and static probabilistic timing analysis (SPTA) for multipath programs running on a hardware platform that uses an evict-on-miss random cache replacement policy. The SPTA computes an upper bound on the probabilistic worst-case execution time (pWCET) of the program, which is an exceedance function giving the probability that the execution time of the program will exceed any given value on any particular run. The pCRPD analysis determines the maximum effect of a pre-emption on the pWCET. The integration between SPTA and pCRPD updates the pWCET to account for the effects of one or more pre-emptions at any arbitrary points in the program. This integration is a necessary step enabling effective schedulability analysis for probabilistic hard real-time systems that use pre-emptive or co-operative scheduling. The analysis is illustrated via a number of benchmark programs.