CXL Persistent Memory is a cutting-edge innovation that merges the strengths of DRAM and NAND flash memory, making a cost-benefit memory layer with still good performance between traditional DRAM and storage.
The core of CXL Persistent Memory can operate in two distinct modes, persistent and non-persistent, each tailored to specific needs. In the persistent mode, a combination of small-capacity DRAM and large-capacity NAND flash memory (e.g., 128GB) works synergistically to create a storage-scale addressing space (64-128GB). Every operation within this addressing space is made persistent and ensures data remains intact even in the event of power loss.
The DRAM in persistent-mode setup serves as an intelligent cache for NAND, significantly enhancing read performance. When a 64B access misses on DRAM, the management core will swiftly retrieve the necessary page containing desired 64B data from NAND and brings it back to NAND when updated.
One significant advantage of CXL Persistent Memory lies in its reduced dependence on large-capacity DRAM and removes the need for large supercaps, which have been a key requirement in NVMDIMM-N memory. Instead, it strikes an ideal balance, offering performance comparable to the concept of storage-class-memory which bridges the gap between DRAM and traditional storage.
In the non-persistent mode, our core offers flexibility by allowing the use of a larger DRAM. Utilizing a spacious DRAM cache combined with NAND flash memory, our technology can create a DRAM-like addressing space for the host to access with direct memory protocols. The management strategy for both DRAM and NAND will efficiently identify hot data to reside in DRAM while cold data is placed back into NAND, which optimizes system responsiveness and resource allocation.