Predictor-Directed Stream Buffers

Timothy Sherwood, Suleyman Sair, and Brad Calder

In proceedings of the 33rd International Symposium on Microarchitecture, December 2000.


An effective method for reducing the effect of load latency in modern processors is data prefetching. One form of data prefetching, stream buffers, has been shown to be particularly effective due to its' ability to detect data streams and run ahead of them, prefetching as it goes. Unfortunately, in the past, the applicability of streaming was limited to stride intensive code.

In this paper we propose Predictor-Directed Stream Buffers (PSB), a scheme in which the stream buffer follows an address prediction stream instead of a fixed stride. In addition, we examine using confidence techniques to guide the allocation and prioritization of stream buffers and their prefetch requests. Our results show for pointer-based applications that PSB provides a 30% speedup on average over no prefetching, and provides an average 10% speedup over using previously proposed stride-based stream buffers for pointer-intensive applications.