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Difference Engine: Harnessing Memory Redundancy in Virtual Machines

delete2010-10-01
delete138
PRE
AI
D
Diwaker Gupta
S
Sangmin Lee
M
Michael Vrable
S
Stefan Savage
A
Alex C. Snoeren
G
George Varghese
G
Geoffrey M. Voelker
A
Amin Vahdat
DOI:10.1145/1831407.1831429delete
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Abstract

Abstract

En 中文
Virtual machine monitors (VMMs) are a popular platform for Internet hosting centers and cloud-based compute services. By multiplexing hardware resources among virtual machines (VMs) running commodity operating systems, VMMs decrease both the capital outlay and management overhead of hosting centers. Appropriate placement and migration policies can take advantage of statistical multiplexing to effectively utilize available processors. However, main memory is not amenable to such multiplexing and is often the primary bottleneck in achieving higher degrees of consolidation. Previous efforts have shown that content-based page sharing provides modest decreases in the memory footprint of VMs running similar operating systems and applications. Our studies show that significant additional gains can be had by leveraging both subpage level sharing (through page patching) and incore memory compression. We build Difference Engine, an extension to the Xen VMM, to support each of these-in addition to standard copy-on-write full-page sharing-and demonstrate substantial savings across VMs running disparate workloads (up to 65%). In head-to-head memory-savings comparisons, Difference Engine outperforms VMware ESX server by a factor 1.6-2.5 for heterogeneous workloads. In all cases, the performance overhead of Difference Engine is less than 7%.
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Journal

Communications of the ACM cover
Communications of the ACM
IF:
12.2
Papers:
1.2W
Citations:
3.7W

Organization

University of California System cover
University of California System
Scholars:
37.5W
Papers: 33.7W
Citations: 6.6K