Proceedings of the 23rd Int'l Conference on Supercomputing (ICS), pp. 115~126, Eugene, OR, June 2013.
This paper addresses new system design issues that will occur when a large quantity of emerging persistent RAM (PRAM) is put on the main memory bus of a platform. First, we anticipate that continued technology advances will enable us to integrate (portions of) the system storage within the PRAM modules on a system board. This change clals for comprehensive re-examinzation of the system design concepts that assume slow disk and the block I/O concept. Next, we propose Memorage, a system architecture that virtually manages all available physical resources for memory and storage in an integrated manner. Memorage leverages the existing OS virtual memory (VM) manager to improve the performance of memory-intensive workloads and achieve longer lifetime of the main memory. We design and implement a prototype system in the Linux OS to study the effectiveness of Memorage. Obtained results are promising; Memorage is shown to offer additional physical memory capacity to demanding workloads much more efficiently than a conventional VM manager. Under memory pressure, the performance of studied memory-intensive multiprogramming workloads was improved by up to 40.5% with an average of 16.7%. Moreover, Memorage is shown to extend the lifetime of the PRAM main memory by 3.9 or 6.9 times on a system with 8 GB PRAM main memory and a 240 GB or 480 GB PRAM storage.