Computer Science ETDs


Zheng Cui

Publication Date



Virtual Ethernet overlay provides a powerful model for realizing virtual distributed and parallel computing systems with strong isolation, portability, and recoverability properties. However, in extremely high throughput and low latency networks, such overlays can suffer from bandwidth and latency limitations, which is of particular concern in HPC environments. Through a careful and quantitative analysis, I iden- tify three core issues limiting performance: delayed and excessive virtual interrupt delivery into guests, copies between host and guest data buffers during encapsulation, and the semantic gap between virtual Ethernet features and underlying physical network features. I propose three novel optimizations in response: optimistic timer- free virtual interrupt injection, zero-copy cut-through data forwarding, and virtual TCP offload. These optimizations improve the latency and bandwidth of the overlay network on 10 Gbps Ethernet and InfiniBand interconnects, resulting in near-native performance for a wide range of microbenchmarks and MPI application benchmarks.




Virtualization, Virtual Networking, Networking, High Performance Computing, Performance Optimization, InfiniBand, 10 Gbps Ethernet

Document Type


Degree Name

Computer Science

Level of Degree


Department Name

Department of Computer Science

First Advisor

Bridges, Patrick G.

First Committee Member (Chair)

Arnold, Dorian

Second Committee Member

Crandall, Jedidiah R.

Third Committee Member

Dinda, Peter A.

Fourth Committee Member

Ghani, Nasir

Project Sponsors

Department of Energy; National Science Foundation