The number and diversity of consumer devices are growing rapidly, alongside their target applications' memory consumption. Unfortunately, DRAM scalability is becoming a limiting factor to the available memory capacity in consumer devices. As a potential solution, manufacturers have introduced emerging non-volatile memories (NVMs) into the market, which can be used to increase the memory capacity of consumer devices by augmenting or replacing DRAM. Since entirely replacing DRAM with NVM in consumer devices imposes large system integration and design challenges, recent works propose extending the total main memory space available to applications by using NVM as swap space for DRAM. However, no prior work analyzes the implications of enabling a real NVM-based swap space in real consumer devices. In this work, we provide the first analysis of the impact of extending the main memory space of consumer devices using off-the-shelf NVMs. We extensively examine system performance and energy consumption when the NVM device is used as swap space for DRAM main memory to effectively extend the main memory capacity. For our analyses, we equip real web-based Chromebook computers with the Intel Optane SSD, which is a state-of-the-art low-latency NVM-based SSD device. We compare the performance and energy consumption of interactive workloads running on our Chromebook with NVM-based swap space, where the Intel Optane SSD capacity is used as swap space to extend main memory capacity, against two state-of-the-art systems: (i) a baseline system with double the amount of DRAM than the system with the NVM-based swap space; and (ii) a system where the Intel Optane SSD is naively replaced with a state-of-the-art (yet slower) off-the-shelf NAND-flash-based SSD, which we use as a swap space of equivalent size as the NVM-based swap space.

翻译：消费类设备的数量和种类快速增长，其目标应用的内存消耗也随之增加。然而，DRAM的可扩展性正成为消费类设备可用内存容量的制约因素。作为潜在解决方案，制造商已将新兴非易失性存储器（NVM）引入市场，可通过扩展或替换DRAM来提升消费类设备的内存容量。由于在消费类设备中完全用NVM替换DRAM会带来巨大的系统集成和设计挑战，近期研究提出通过将NVM用作DRAM的交换空间来扩展应用可用的主内存空间。但尚无先前工作分析在实际消费类设备中启用基于真实NVM的交换空间所产生的影响。本研究首次分析了使用现成NVM扩展消费类设备主内存空间的影响。我们全面考察了将NVM设备用作DRAM主内存的交换空间以有效扩展主内存容量时的系统性能与能耗。为进行分析，我们为实际基于网络的Chromebook计算机配备了英特尔Optane SSD（一种基于NVM的低延迟固态硬盘设备）。我们将使用NVM交换空间（通过英特尔Optane SSD容量扩展主内存）的Chromebook上交互式工作负载的性能与能耗，与两种现有先进系统进行对比：(i) 基线系统——DRAM容量为采用NVM交换空间系统的两倍；(ii) 对比系统——将英特尔Optane SSD简单替换为现成（但速度较慢）的NAND闪存SSD（其交换空间容量与NVM交换空间相同）。