UIMigrate: Adaptive Data Migration for Hybrid Non-Volatile Memory Systems
Yujuan Tan1,a, Baiping Wang1, Zhichao Yan2, Qiuwei Deng1, Xianzhang Chen1 and Duo Liu1,b
1Chongqing University, China
atanyujuan@gmail.com
bliuduo@cqu.edu.cn
2University of Texas at Arlington, USA
ABSTRACT
Byte-addressable, non-volatile memory (NVRAM) combines the benefits of DRAM and flash memory. Its slower speed compared to DRAM, however, makes it hard to entirely replace DRAM with NVRAM. Hybrid NVRAM systems that equip both DRAM and NVRAM on the memory bus become a better solution: frequently accessed, hot pages can be stored in DRAM while other cold pages can reside in NVRAM. This way, the system gets the benefits of both high performance (from DRAM) and lower power consumption and cost/performance (from NVRAM). Realizing an efficient hybrid NVRAM system requires careful page migration and accurate data temperature measurement. Existing solutions, however, often cause invalid migrations due to inaccurate data temperature accounting, because hot and cold pages are separately identified in DRAM and NVRAM regions.
Based on this observation, we propose UIMigrate, an adaptive data migration approach for hybrid NVRAM systems. The key idea is to consider data temperature across the whole DRAMNVRAM space when determining whether a page should be migrated between DRAM and NVRAM. In addition, UIMigrate adapts workload changes by dynamically adjusting migration decisions as workload changes. Our experiments using SPEC 2006 show that UIMigrate can reduce the number of migrations and improves performance by up to 90.4% compared to existing state-of-the-art approaches.
