This paper explores the relationship between domain scheduling in a virtual machine monitor (VMM) and I/O performance. Traditionally, VMM schedulers have focused on fairly sharing the processor resources among domains while leaving the scheduling of I/O resources as a secondary concern. However, this can result in poor and/or unpredictable application performance, making virtualization less desirable for applications that require efficient and consistent I/O behavior.
This paper is the first to study the impact of the VMMscheduler on performance using multiple guest domains concurrently running different types of applications. In particular, different combinations of processor-intensive, bandwidth-intensive, and latencysensitive applications are run concurrently to quantify the impacts of different scheduler configurations on processor and I/O performance. These applications are evaluated on 11 different scheduler configurations within the Xen VMM. These configurations include a variety of scheduler extensions aimed at improving I/O performance. This cross product of scheduler configurations and application types offers insight into the key problems in VMM scheduling
for I/O and motivates future innovation in this area.
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Authors: Diego Ongaro, Alan L. Cox, and Scott Rixner
Date: March 2008
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Please note there are slides to accompany this paper|||||http://www.cs.rice.edu/CS/Architecture/docs/ongaro-vee08.pdf