Note: hfalk, ESD, WCC

Abstract: Caches are notorious for their unpredictability. It is difficult or even impossible to predict if a memory access will result in a definite cache hit or miss. This unpredictability is highly undesired especially when designing real-time systems where the worst-case execution time (WCET) is one of the key metrics. Scratchpad memories (SPMs) have proven to be a fully predictable alternative to caches. In contrast to caches, however, SPMs require dedicated compiler support.<br /> This paper presents an optimal static SPM allocation algorithm for program code. It minimizes WCETs by placing the most beneficial parts of a program's code in an SPM. Our results underline the effectiveness of the proposed techniques. For a total of 73 realistic benchmarks, we reduced WCETs on average by 7.4% up to 40%. Additionally, the run times of our ILP-based SPM allocator are negligible.