Reducing Cache Traffic and Energy with Macro Data Load

Abstract

This paper presents a study on macro data load, an efficient mechanism to enhance loaded value reuse. A macro data load brings into the processor a maximum-width data value the cache port allows, saves it in an internal structure, and facilitates reuse by later loads. A comprehensive limit study using a generalized memory value reuse table (MVRT) shows the significantly increased reuse opportunities provided by macro data load. We also describe a modified load store queue design as an implementation of the proposed concept. Our quantitative study shows that over 35% of L1 cache accesses in the SPEC2k integer and MiBench programs can be eliminated, resulting in a related energy reduction of 24% and 35% on average, respectively