Title
An empirical study of memory sharing in virtual machines
Abstract
Content-based page sharing is a technique often used in virtualized environments to reduce server memory requirements. Many systems have been proposed to capture the benefits of page sharing. However, there have been few analyses of page sharing in general, both considering its real-world utility and typical sources of sharing potential. We provide insight into this issue through an exploration and analysis of memory traces captured from real user machines and controlled virtual machines. First, we observe that absolute sharing levels (excluding zero pages) generally remain under 15%, contrasting with prior work that has often reported savings of 30% or more. Second, we find that sharing within individual machines often accounts for nearly all (90%) of the sharing potential within a set of machines, with inter-machine sharing contributing only a small amount. Moreover, even small differences between machines significantly reduce what little inter-machine sharing might otherwise be possible. Third, we find that OS features like address space layout randomization can further diminish sharing potential. These findings both temper expectations of real-world sharing gains and suggest that sharing efforts may be equally effective if employed within the operating system of a single machine, rather than exclusively targeting groups of virtual machines.
Year
Venue
Keywords
2012
USENIX Annual Technical Conference
server memory requirement,memory sharing,absolute sharing level,zero page,virtual machine,real-world utility,inter-machine sharing,content-based page sharing,sharing potential,real-world sharing gain,empirical study,page sharing
Field
DocType
Citations 
Virtual machine,Memory sharing,Computer science,Address space layout randomization,Real-time computing,Empirical research,Distributed computing
Conference
35
PageRank 
References 
Authors
1.27
11
4
Name
Order
Citations
PageRank
Sean Barker11887.93
Timothy Wood2168189.36
Prashant J. Shenoy36386521.30
Ramesh K. Sitaraman41928141.68