DFShards

Abstract

The Miss Ratio Curve (MRC) describes the cache miss ratio as a function of the cache size. It has various shapes that represent the data access behaviors of workloads in the cache. MRC is an effective tool to guide cache partitioning, but its real-time construction is challenging. Miniature Simulation is a novel approach that constructs MRCs for non-stack algorithms in real time, via feeding a small number of sample references to multiple mini caches simultaneously to get the miss ratios. However, while using the Miniature Simulation, the size and number of mini-caches are difficult to set before the program runs. First, it may set too many mini-caches and cause repeated simulations. Second, it may miss some important cache sizes and consequently construct a less precise shape of MRC and result in incorrect cache partitioning. To address this problem, we propose DFShards, an adaptive cache shards (mini-caches) configuration approach based on program access patterns. The key idea is to dynamically adjust the configuration of the cache shards, including the number of the total cache shards and the size of each cache shard, based on the access behaviors to reflect changes in workload to build an precise MRC, thereby achieving better cache partitioning and overall performance. Our extensive experiments show that DFShards can construct precise MRCs in real-time during program running. Compared to the state-of-the-art approaches, it can save up to 47% of the cache space for MRC constructions while increasing the cache hit ratio by up to 17%.