Multistep Tag Comparison Method for a Low-Power L2 Cache

Abstract

We present novel ways to predict both cache hits and misses during tag comparison in a high-associative cache. We present a partial-tag enhanced Bloom filter to improve the accuracy of the cache miss prediction method and hot/cold checks that control data liveness to reduce the tag comparisons of the cache hit prediction method. We also combine the two methods so that their order of application can be dynamically adjusted to adapt to changing cache access behavior

this adaptability further reduces tag comparisons. In experiments the proposed method reduced the energy consumption of tag comparison by an average of 88.40%, which translates to an average reduction of 35.34% (40.19% with low-power data access) in the total energy consumption of the L2 cache and a further reduction of 8.86% (10.07% with low-power data access) when compared with existing methods.