Main memory (DRAM) significantly impacts the power and energy utilization of the overall server system. Non-Volatile Memory (NVM) devices, such as Phase Change Memory and Spin-Transfer Torque RAM, are suitable candidates for main memory to reduce energy consumption. But unlike DRAM, NVMs access latencies are higher than DRAM and NVM writes are more energy sensitive than DRAM write operations. Thus, Hybrid Main Memory Systems (HMMS) employing DRAM and NVM have been proposed to reduce the overall energy depletion of main memory while optimizing the performance of NVM. This paper proposes eMap, an optimal heap memory object placement planner in HMMS. eMap considers the object-level access patterns and energy consumption at the application level and provides an ideal placement strategy for each object to augment performance and energy utilization. eMap is equipped with two modules, eMPlan and eMDyn. Specifically, eMPlan is a static placement planner which provides one time placement policies for memory object to meet the energy budget while eMDyn is a runtime placement planner to consider the change in energy limiting constraint during the runtime and shuffles the memory objects by taking into account the access patterns as well as the migration cost in terms of energy and performance. The evaluation shows that our proposed solution satisfies both the energy limiting constraint and the performance. We compare our methodology with the state-of-the-art memory object classification and allocation (MOCA) framework. Our extensive evaluation shows that our proposed solution, eMPlan meets the energy constraint with 4.17 times less costly and reducing the energy consumption up to 14% with the same performance. eMDyn also satisfies the performance and energy requirement while considering the migration cost in terms of time and energy.

中文翻译：

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在能量受限的混合内存系统中优化堆内存对象的放置

主内存 (DRAM) 显着影响整个服务器系统的功率和能源利用率。非易失性存储器 (NVM) 设备，例如相变存储器和自旋转移扭矩 RAM，是主存储器的合适候选者，以降低能耗。但与 DRAM 不同的是，NVM 访问延迟高于 DRAM，并且 NVM 写入比 DRAM 写入操作对能量更敏感。因此，已经提出采用 DRAM 和 NVM 的混合主存储器系统 (HMMS) 来减少主存储器的整体能量消耗，同时优化 NVM 的性能。本文提出了 HMMS 中最佳堆内存对象放置规划器 eMap。eMap 在应用层考虑对象级访问模式和能源消耗，并为每个对象提供理想的放置策略，以提高性能和能源利用率。eMap 配备了两个模块，eMPlan 和 eMDyn。具体来说，eMPlan 是一个静态布局规划器，它为内存对象提供一次性布局策略以满足能量预算，而 eMDyn 是一个运行时布局规划器，以考虑运行时能量限制约束的变化，并通过考虑访问模式以及能源和性能方面的迁移成本。评估表明，我们提出的解决方案满足能量限制约束和性能。我们将我们的方法与最先进的内存对象分类和分配 (MOCA) 框架进行比较。我们的广泛评估表明，我们提出的解决方案 eMPlan 满足能量约束 4。在性能相同的情况下，成本降低 17 倍，能耗降低 14%。eMDyn 还满足性能和能源要求，同时考虑了时间和能源方面的迁移成本。