DRE system performance optimization with the SMACK cache efficiency metric

• Empirical evidence that search-based optimization of software deployment, using placement heuristics designed to increase cache performance, can yield substantial performance benefits.
• SMACK, a formalized and minimalistic model for calculating the relative cache performance increase of various software deployments.
• Detailed discussion on the challenges of considering cache effects when optimizing software system deployment.

System performance improvements are critical for the resource-limited environment of multiple integrated applications executing inside a single distributed real-time and embedded (DRE) system, such as integrated avionics platform or vehtronics systems. While processor caches can effectively reduce execution time there are several factors, such as cache size, system data sharing, and task execution schedule, which make it hard to quantify, predict, and optimize the cache usage of a DRE system. This article presents SMACK, a novel heuristic for estimating the hardware cache usage of a DRE system, and describes a method of varying the runtime behavior of DRE system software without (1) requiring extensive safety recertification or (2) violating the real-time scheduling deadlines. By using SMACK as a maximization target, we were able to reduce integrated DRE system execution time by an average of 2.4% and a maximum of 4.34%.