论文标题
Caram：内容感知的混合PCM/DRAM主存储系统框架
CARAM: A Content-Aware Hybrid PCM/DRAM Main Memory System Framework
论文作者
论文摘要
相变内存（PCM）的出现提供了将持续内存连接到主内存总线的机会。尽管PCM达到了高读取吞吐量和较低的待机功率，但关键的问题是其写入性能和耐用性有限，尤其是与DRAM相比。自然启发的设计是融合DRAM和PCM的混合内存体系结构，以利用两种内存的正面方面。不幸的是，现有的解决方案受到有限的主内存大小的挑战，这是内存计算的主要瓶颈。在本文中，我们介绍了一种新颖的内容意识到混合PCM/DRAM主存储系统框架-Caram，该框架利用了重复数据删除以提高内存效率的线路共享。 Caram通过删除不必要的重复线条写入有效地减少了将流量写入混合记忆。它还通过合并混合记忆中的冗余线条，从而实质上扩展了可用的自由记忆空间，从而进一步提高了PCM的磨损水平效率。为了获得高数据访问性能，我们还设计了一套加速技术，以最大程度地减少额外的计算成本引起的间接费用。我们的实验结果表明，与混合系统相比，Caram有效地减少了15％〜42％的记忆使用情况，并将I/O带宽提高13％〜116％，而节省31％〜38％的能耗。
The emergence of Phase-Change Memory (PCM) provides opportunities for directly connecting persistent memory to main memory bus. While PCM achieves high read throughput and low standby power, the critical concerns are its poor write performance and limited durability, especially when compared to DRAM. A naturally inspired design is the hybrid memory architecture that fuses DRAM and PCM, so as to exploit the positive aspects of both types of memory. Unfortunately, existing solutions are seriously challenged by the limited main memory size, which is the primary bottleneck of in-memory computing. In this paper, we introduce a novel Content Aware hybrid PCM/DRAM main memory system framework - CARAM, which exploits deduplication to improve line sharing with high memory efficiency. CARAM effectively reduces write traffic to hybrid memory by removing unnecessary duplicate line writes. It also substantially extends available free memory space by coalescing redundant lines in hybrid memory, thereby further improving the wear-leveling efficiency of PCM. To obtain high data access performance, we also design a set of acceleration techniques to minimize the overhead caused by extra computation costs. Our experiment results show that CARAM effectively reduces 15%~42% of memory usage and improves I/O bandwidth by 13%~116%, while saving 31%~38% energy consumption, compared to the state-of-the-art of hybrid systems.
