Cache Resident Data Locality Analysis

The data cache organization of a computer can significantly affect overall data access latencies when a program is executed. The cache performance depends on the locality characteristics of the data being processed in a program as well as the underlying architecture. A typical executing program has a data access profile that exhibits both temporal and spatial locality characteristics. Since most processors contain single data caches at a given level and since the single data cache cannot be optimized for purely spatial nor purely temporal locality data accesses, cache space pollution and inefficient usage of cache resources can occur. In the worst case, these phenomena can actually introduce additional data access latency through repeated line fills. Here an analysis and modeling scheme is presented that describes the runtime data access behavior of several benchmark programs in a typical, unified data cache. The motivation for the development of this model is to produce information that may aid in the design of a split data cache with one side optimized for temporal locality accesses and the other for spatial locality accesses.