Scott Rixnerr
Diego Ongaro, Alan L. Cox, and Scott Rixner
Rice University
Scheduling Pitfalls for I/O-intensive Guests
******
This presentation explores the relationship between domain scheduling in
Xen and I/O performance.  We study the impact of the VMM scheduler on
processor and I/O performance using multiple guest domains concurrently
running different combinations of processor-intensive,
bandwidth-intensive, and latency-sensitive applications.  These
applications are evaluated on a variety different scheduler
configurations within the Xen VMM. We find that, in general, the
scheduler focuses on fairly sharing processor resources which can result
in poor and/or unpredictable performance for applications that require
efficient and consistent I/O behavior.  These results offer insight into
the key problems in VMM scheduling for I/O and motivate future
innovation in this area.