基於相變化記憶體整合記憶體與儲存裝置之轉換層設計

Abstract

相變化記憶體技術在未來被認為是相當有潛力的主記憶體和儲存材 料。這篇研究提出與過去研究不同的觀察與設計,藉由觀察作業系統 使用主記憶體的行為加上了解儲存裝置的使用特徵,來設計機制提升 系統的效能與可靠程度。實際上,我們在此記憶體材料上提出管理方 法,使上層系統能在不做任何更動的情況下,更有效率地善用相變化 記憶體的優勢來提升整體效能。另一方面,相變化記憶體空間能夠被 有效率地使用,更能大大提升整個裝置的壽命。除此之外,我們還提 出了三個指令設計來幫助作業系統開發者善用此設計的潛力,來加速 應用程序運作時初始化和終止的時間以及降低儲存裝置輸入輸出所耗 費的額外負擔。實驗的結果也能夠證實我們提出相變化記憶體同時當 作主記憶體和儲存裝置的轉換層設計,即使套用一個粗略而簡單的管 理方法,也能夠明顯地提升整體系統的效能並能夠保證合理的產品壽 命。

Phase change memory (PCM) is known for its potentials as the main mem- ory and even jointly as a storage medium. Different from the past work, this work presents a PCM translation layer that considers how the main memory is used by the operating system together with the usage patterns of storage devices by trading their performance and reliability. In particular, a man- agement scheme is proposed to improve the capability of PCM as the main memory (and the performance of the entire system) by utilizing the potentially larger capacity of a PCM storage space for endurance enhancement without any modifications to the existing operating system implementations. More- over, three commands are proposed to help operating system engineers to take advantage of PCM as both the main memory and a storage medium by reduc- ing I/O overheads and speeding up both the initialization and termination of program executions. The experimental results show that the performance of PCM as both main memory and storage can be significantly improved with reasonable lifetime, while the system overhead is very limited under coarse- grained wear leveling.