As cloud computing and big data applications become more popular, the demand for large capacity memory and data preservation in memory increases. Therefore, nonvolatile memory (NVM) with high capacity is being actively developed. A hybrid memory that comprises both NVM and DRAM and provides both high access speed and nonvolatility has become a major trend. However, compared to DRAM, NVM in the hybrid memory typically suffers from a shorter lifetime and higher latency. To improve the lifetime and address the latency issues associated with hybrid memory, we propose a global clean page first replacement (GCPF) to reduce the write operations to NVM. We also propose an index-aware multistream prefetcher (IAMSP) that considers the indexes of prefetch candidates individually so as to prefetch pages from NVM more accurately. Benchmarks with a large memory footprint are used to evaluate the proposed schemes. The experimental results show that GCPF enhances lifetime by 56.8% as compared to LRU, on average. When applying prefetching schemes on GCPF, the lifetime is insignificantly degraded. In addition, IAMSP reduces DRAM misses by 42.0% as compared to LRU, while a modern prefetcher that can change the prefetch degree dynamically only reduces DRAM misses by 38.0%, on average. When applying both GCPF and IAMSP, the average access latency can be reduced by 28.8% as compared to LRU.

中文翻译：

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混合内存架构中的全局清洁页面优先替换和索引感知多流预取器

随着云计算和大数据应用的普及，对大容量内存和内存中数据保存的需求增加。因此，正在积极开发具有高容量的非易失性存储器（NVM）。包含 NVM 和 DRAM 并提供高访问速度和非易失性的混合存储器已成为主要趋势。然而，与 DRAM 相比，混合内存中的 NVM 通常具有更短的使用寿命和更高的延迟。为了提高生命周期并解决与混合内存相关的延迟问题，我们提出了全局干净页面优先替换 (GCPF) 以减少对 NVM 的写入操作。我们还提出了一种索引感知多流预取器（IAMSP），它单独考虑预取候选者的索引，以便更准确地从 NVM 预取页面。具有大内存占用的基准用于评估所提出的方案。实验结果表明，与 LRU 相比，GCPF 的寿命平均提高了 56.8%。当在 GCPF 上应用预取方案时，生命周期不会显着降低。此外，与 LRU 相比，IAMSP 将 DRAM 未命中减少了 42.0%，而可以动态更改预取程度的现代预取器平均仅将 DRAM 未命中减少了 38.0%。当同时应用 GCPF 和 IAMSP 时，与 LRU 相比，平均访问延迟可以减少 28.8%。0% 与 LRU 相比，而可以动态改变预取程度的现代预取器平均只能将 DRAM 未命中率降低 38.0%。当同时应用 GCPF 和 IAMSP 时，与 LRU 相比，平均访问延迟可以减少 28.8%。0% 与 LRU 相比，而可以动态改变预取程度的现代预取器平均只能将 DRAM 未命中率降低 38.0%。当同时应用 GCPF 和 IAMSP 时，与 LRU 相比，平均访问延迟可以减少 28.8%。