Using Prime Numbers for Cache Indexing to Eliminate Conflict Misses

Using alternative cache indexing/hashing functions is a popular technique to reduce conflict misses by achieving a more uniform cache access distribution across the sets in the cache. Although various alternative hashing functions have been demonstrated to eliminate the worst case conflict behavior, no study has really analyzed the pathological behavior of such hashing functions that often result in performance slowdown. In this paper, we present an in-depth analysis of the pathological behavior of cache hashing functions. Based on the analysis, we propose two new hashing functions: prime modulo and prime displacement that are resistant to pathological behavior and yet are able to eliminate the worst case conflict behavior in the L2 cache. We show that these two schemes can be implemented in fast hardware using a set of narrow add operations, with negligible fragmentation in the L2 cache. We evaluate the schemes on 23 memory intensive applications. For applications that have non-unifo...

• Type: Conference
• Year: 2004
• Where: HPCA
• Authors: Mazen Kharbutli, Keith Irwin, Yan Solihin, Jaejin Lee
• Keywords: Alternative Hashing Functions, Cache Hashing Functions, Cache Indexing/hashing Functions, Computer Architecture, HPCA 2004