Native DRAM Cache: Re-architecting DRAM As a Large-Scale Cache for Data Centers

Contemporary data center CPUs are experiencing an unprecedented surge in core count. This trend necessitates scrutinized Last-Level Cache (LLC) strategies to accommodate increasing capacity demands. While DRAM offers significant capacity, using it as a cache poses challenges related to latency and energy. This paper introduces Native DRAM Cache (NDC), a novel DRAM architecture specifically designed to operate as a cache. NDC features innovative approaches, such as conducting tag matching and way selection within a DRAM subarray and repurposing existing precharge transistors for tag matching. These innovations facilitate Caching-In-Memory (CIM) and enable NDC to serve as a high-capacity LLC with high set-associativity, low-latency, high-throughput, and low-energy. Our evaluation demonstrates that NDC significantly outperforms state-of-the-art DRAM cache solutions, enhancing performance by 2.8%/52.5%/44.2% (up to 8.4%/140.6%/85.5%) in SPEC/NPB/GAP benchmark suites, respectively.