Open AccessCAWR: Buffer Replacement with Channel‐Aware Write Reordering Mechanism for SSDs
Author(s) -
Wang Ronghui,
Chen Zhiguang,
Xiao g,
Zhang Minxuan,
Dong Weihua
Publication year - 2015
Publication title -
etri journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.295
H-Index - 46
eISSN - 2233-7326
pISSN - 1225-6463
DOI - 10.4218/etrij.15.0114.0055
Subject(s) - exploit , computer science , locality , schedule , parallel computing , channel (broadcasting) , garbage collection , locality of reference , parallelism (grammar) , computer network , garbage , operating system , cache , philosophy , linguistics , computer security , programming language
A typical solid‐state drive contains several independent channels that can be operated in parallel. To exploit this channel‐level parallelism, a variety of works proposed to split consecutive write sequences into small segments and schedule them to different channels. This scheme exploits the parallelism but breaks the spatial locality of write traffic; thus, it is able to significantly degrade the efficiency of garbage collection. This paper proposes a channel‐aware write reordering (CAWR) mechanism to schedule write requests to different channels more intelligently. The novel mechanism encapsulates correlated pages into a cluster beforehand. All pages belonging to a cluster are scheduled to the same channels to exploit spatial locality, while different clusters are scheduled to different channels to exploit the parallelism. As CAWR covers both garbage collection and I/O performance, it outperforms existing schemes significantly. Trace‐driven simulation results demonstrate that the CAWR mechanism reduces the average response time by 26% on average and decreases the valid page copies by 10% on average, while achieving a similar hit ratio to that of existing mechanisms.