Getting 10 Gb/s from Xen: Safe and Fast Device Access from Unprivileged Domains

The networking performance available to Virtual Machines (VMs) can be low due to the inefficiencies of transferring network packets between the host domain and guests. This can limit the application-level performance of VMs on a 10 Gb/s network. To improve network performance, we have created a “virtualization aware” smart network adapter and modified Xen1 to allow direct, but safe, access to such adapters from guest operating systems. Networking overheads are reduced considerably, and the host domain is removed as a bottleneck, resulting in significantly improved performance. We describe our modifications to the Xen networking architecture that allow guest kernels direct — but secure — access to the networking hardware, whilst preserving support for migration. We also describe briefly how the same technology is used to grant direct network access to userlevel applications and thus provide even greater efficiency in terms of bandwidth, latency and CPU utilisation.

• Type: Conference
• Year: 2007
• Where: EUROPAR
• Authors: Kieran Mansley, Greg Law, David Riddoch, Guido Barzini, Neil Turton, Steven Pope
• Keywords: EUROPAR 2007, Host Domain, Networking Performance, Smart Network Adapter