Adaptive Cache Management for a combined SRAM and DRAM Cache Hierarchy for Multi-Cores

On-chip DRAM caches may alleviate the memory bandwidth problem in future multi-core architectures through reducing off-chip accesses via increased cache capacity. For memory intensive applications, recent research has demonstrated the benefits of introducing high capacity on-chip L4-DRAM as Last-Level-Cache between L3-SRAM and off-chip memory. These multi-core cache hierarchies attempt to exploit the latency benefits of L3-SRAM and capacity benefits of L4-DRAM caches. However, not taking into consideration the cache access patterns of complex applications can cause inter-core DRAM interference and inter-core cache contention. In this paper, we contest to re-architect existing cache hierarchies by proposing a hybrid cache architecture, where the Last-Level-Cache is a combination of SRAM and DRAM caches. We propose an adaptive DRAM placement policy in response to the diverse requirements of complex applications with different cache access behaviors. It reduces inter-core DRAM interference and inter-core cache contention in SRAM/DRAM-based hybrid cache architectures: increasing the harmonic mean instruction-per-cycle throughput by 23.3% (max. 56%) and 13.3% (max. 35.1%) compared to state-of-the-art.