Heterogeneous Memory Architecture (HMA) aims to optimize memory usage by leveraging a combination of memory types, such as high-bandwidth memory (HBM), commodity DRAM, and non-volatile memory (NVM), when utilized as main memory. To achieve maximum performance benefits, frequently accessed data pages are prioritized for storage in the faster HBM, while less frequently accessed pages are stored in slower memory types like DRAM or NVM. This enables a more efficient allocation of memory resources and improves overall system performance. In a Flat Address Space memory organization, all memory types, both fast and slow, are treated as a unified memory pool. This approach increases the overall memory capacity accessible to the system. In Flat Address Space organization, frequently accessed data pages may need to be remapped from slower memory to faster memory to improve memory access times. Such relocation requires changes to the data/states in the TLB (TLB shootdown) and the processor cache (cache line invalidations), leading to performance degradation. To address these inefficiencies, we propose a novel solution called Duon. The goal of Duon is to eliminate the overheads associated with page migration in systems using Extended TLB and Page Table. Specifically, our approach ensures that the updated mapping information for remapped pages is carefully stored directly in the TLB and page table itself. By doing so, the need for TLB shootdown and cache line invalidation after page migration is eliminated. Consequently, our proposal results in an overall improvement in IPC by 3.87% over existing state-of-the-art techniques, enhancing the efficiency and performance of heterogeneous memory systems. Further, our approach can work with any of the existing page migration policies and improve the performance.

翻译：异构内存架构（HMA）旨在通过结合多种内存类型（如用作主内存的高带宽内存HBM、商用DRAM和非易失性内存NVM）来优化内存使用。为获得最大性能收益，频繁访问的数据页优先存储在更快的HBM中，而访问不频繁的页则存储在DRAM或NVM等较慢内存类型中。这种方式能够更高效地分配内存资源，并提升整体系统性能。在扁平地址空间内存组织模式下，所有内存类型（包括快慢内存）均被视为统一内存池，从而增加系统可访问的总内存容量。在扁平地址空间组织中，频繁访问的数据页可能需要从慢速内存重映射至快速内存以改善内存访问时间。此类重定位需要更改TLB（TLB刷除）和处理器缓存（缓存行无效化）中的数据/状态，导致性能下降。为解决这些低效问题，我们提出一种名为Duon的创新解决方案。Duon的目标是消除基于扩展TLB与页表的系统中页面迁移带来的开销。具体而言，我们的方法确保重映射页的更新映射信息被精确地直接存储在TLB和页表本身中。通过这种方式，页面迁移后无需进行TLB刷除和缓存行无效化。因此，我们的方案相比现有最先进技术整体IPC提升3.87%，增强了异构内存系统的效率与性能。此外，该方法可适配任意现有页面迁移策略并提升性能。