Modeling and Analyzing of 3D DRAM as L3 Cache Based on DRAMSim2

Cache memory system with a die-stacking DRAM L3 cache is a promising answer to break the Memory Wall and has a positive effect on performance. In order to further optimize the existing memory system, in this paper, a 3D DRAM as L3 Cache is modeled and analyzed based on DRAMSim2 simulator. In order to use an on-die DRAM as cache, tags and data are combined in one row in the DRAM, meanwhile, utilize the 3D DRAM with wider bus width and denser capacity. The cache memory modeling platform is evaluated by running traces which simulate the access behavior of core from spec2000 that generated by gem5. With DRAM L3 cache, all the test traces experience an improvement of performance. Read operation has an average speed-up of 1.82x over the baseline memory system, while write operation is 6.38x. The improvement of throughput in 3D DRAM cache compared to baseline system can reach to 1.45x's speedup.