A Quantitative Evaluation of Cache Types for High-Performance Computer Systems

Parallel accesses to the table lookaside buffer (TLB) and cache array are crucial for high-performance computer systems, and the choice of cache types is one of the most important factors affecting cache performance. In this paper we classify caches according to both index and tag. Since both index and tag could be either virtual (V) or real (R), our classification results in four combinations or cache types. The real address caches with virtual tags for high-performance computer systems in our study are prediction-based, since index bins are generated from a small array and predictions could be false. As a result, we also discuss and evaluate real address MRU caches with real tags, and propose virtually indexed MRU caches with real tags. Each of the four cache types and MRU caches are discussed and evaluated using trace-driven simulation. Our results show that a virtually indexed MRU cache with real tags i s a good choice for high-performance computer systems.