Virtualization using Xen-based virtual machine environment has yet to permeate the field of high performance computing (HPC). One major requirement for HPC is the availability of scalable and high performance I/O. Conventional wisdom suggests that virtualization of system services must lead to degraded performance. In this presentation, we take on a parallel I/O perspective to study the viability of Xen-based HPC for data-intensive programs. We have analyzed the overheads and migration costs for parallel I/O programs in a Xen-based virtual machine cluster. Our analysis covers PVFS-based parallel I/O over two different networking protocols: TCP-based Gigabit Ethernet and VMM-bypass InfiniBand. Our experimental results suggest that network processing in Xen-based virtualization can significantly impact the performance of Parallel I/O. By carefully tuning the networking layers, we have demonstrated the following for Xen-based HPC I/O: (1) TCP offloading can help achieve low overhead para...
Weikuan Yu, Jeffrey S. Vetter