Hardware versus hybrid data prefetching in multimedia processors: a case study

Data prefetching is a promising technique for hiding the penalties due to compulsory cache misses. In this paper we present a case study on two types of data prefetching in the context of multimedia processing: a purely hardware-based technique and a more low-cost hybrid hardware/software technique. Moreover, we also propose a technique for increasing the so-called prefetch distance in hardware prefetching and a scheme to reduce trashing in the data cache. Our results demonstrate that the low-cost hybrid prefetching scheme slightly outperforms hardware-based prefetching for the code segments for which both solutions have been applied, while hardware prefetching potentially allows more code to benefit from the prefetching.