The Potential and Perils of Multi-Level Memory

The future of memory systems is Multi-Level Memory (MLM). In a MLM system the main memory is comprised of two or more types of memory instead of a conventional DDR-DRAM-only main memory. By combining different memory technologies, an MLM system can potentially offer more usable bandwidth and more capacity for a similar cost as a conventional memory system. However, substantial software and hardware design challenges must be overcome to make this potential real. It is our position that the diversity of application access patterns precludes any simple "one size fits all" approach and that better tools and design processes will be needed to fulfill the potential of MLM. Efficient implementations of MLM will require a high degree of co-design and coordination between hardware and software. The simulation framework we have built for this study can aid tool building to solve the programming challenges.