Where Does the Time Go in Software DSM Systems: Experiences with JIAJIA? Weisong Shi, Weiwu Hu and Zhimin Tang Institute of Computing Technology Chinese Academy of Sciences Beijing 100080, P.R.China E-mail: f wsshi, hww,
[email protected] Abstract
The performance gap between software DSM systems and message passing platforms prevents the prevalence of software DSM system greatly, though great eorts have been delivered in this area in the past decade. In this paper, we take the challenge to nd where should we focus our strength on in the future design. The components of total system overhead of software DSM systems are analyzed in detail rstly. Based on a state-ofthe-art software DSM system JIAJIA, we measure these components on Dawning parallel system and draw ve important conclusions which are dierent from some traditional viewpoints. (1) The performance of the JIAJIA software DSM system is acceptable. For four of eight applications, the parallel eciency achieved by JIAJIA is about 80%, while for two others, 70% eciency can be obtained. (2) 40.94% interrupt service time is overlapped with waiting time. (3) Encoding and decoding dis do not cost much time(