A Working-set Sensitive Page Replacement Policy for PCM-based Swap Systems

Abstract

Abstract-Due to the recent advances in PhageChange Memory (PCM) technologies, a new memory hierarchy of computer systems with PCM is expected to appear. In this paper, we present a new page replacement policy that adopts PCM as a high speed swap device. As PCM has limited write endurance, our goal is to minimize the amount of data written to PCM. To do so, we defer the eviction of dirty pages in proportion to their dirtiness. However, excessive preservation of dirty pages in memory may deteriorate the page fault rate, especially when the memory capacity is not enough to accommodate full working-set pages. Thus, our policy monitors the current working-set size of the system, and controls the deferring level of dirty pages not to degrade the system performances. Simulation experiments show that the proposed policy reduces the write traffic to PCM by 160% without performance degradations.

Acceleration of Storage Performance in Cloud Systems by Using NVRAM

“…With the rapid enhancement of NVRAM technologies like PRAM (phase-change random access memory) and STT-RAM (spin-transfer torque random access memory) [1,2,3,4], it is expected that NVRAM will be used in the memory and storage hierarchies of future cloud servers [5,6,7]. In this article, we perform empirical analysis to see how much performance improvement can be expected if we supplement NVRAM as an additional component of cloud storage.…”

“…For video streaming applications, adopting NVRAM as a ile system area leads to the best performances. Although previous studies on NVRAM have been performed, they focused only on a single usage such as database [8], smartphone [1], journaling [3], swapping [4,9], or cache media [10,11]. Unlike these existing works, this article has a novelty in that it considers various types of applications and storage layers, and performs optimized adoption of the given NVRAM storage.…”