AC/DC: An Adaptive Data Cache Prefetcher

AC/DC is an adaptive method for prefetching data from main memory.The basic prefetch method divides the memory address space into equal-sized concentration zones (CZones), and uses a global history buffer to track and detect patterns in miss address "deltas" (differences between consecutive addresses) within each CZone.When simulated with a realistic desktop memory system, CZone prefetching with Delta Correlations (C/DC) outperforms four other previously proposed prefetching methods.C/DC yields an average performance improvement of 23 percent when compared with no prefetching. Adaptively is then added to the basic method.A tuning algorithm dynamically configures the CZone size and prefetch degree (i.e. the amount of data prefetched) on a per program-phase basis.Adaptive re-configuration provides additional performance improvements of 4% over C/DC.Overall, the Adaptive CZone / Delta Correlation (AC/DC) method outperforms other methods studied by 10%.