Hong Ong

Learn More
—Virtual machine, which typically consists of a guest operating system (OS) and its serial applications, can be checkpointed, migrated to another cluster node, and restarted later to its previous saved state. However, to date, it is nontrivial to provide checkpoint-restart mechanisms with the same level of transparency for distributed applications running(More)
System-level virtualization has been a research topic since the 70's but regained popularity during the past few years because of the availability of efficient solution such as Xen and the implementation of hardware support in commodity processors (e.g. Intel-VT, AMD-V). However, a majority of system-level virtualization projects is guided by the server(More)
In this article, we present some results on the communication performance of TCP/IP in a cluster of Pentium based workstations connected by a Gigabit Ethernet network. The experiments were performed in order to identify the bottlenecks in the communication protocol stack. We outline our performance measurements and suggest means to improve the overall(More)
We evaluate and compare the performance of LAM, MPICH, and MVICH on a Linux cluster connected by a Gigabit Ethernet network. Performance statistics are collected using NetPIPE which show the behavior of LAM/MPI and MPICH over a gigabit network. Since LAM and MPICH use the TCP/IP socket interface for communicating messages, it is critical to have high TCP/IP(More)
Processing nodes of the Cray XT and IBM Blue Gene Massively Parallel Processing (MPP) systems are composed of multiple execution units, sharing memory and network subsystems. These multicore processors offer greater computational power, but may be hindered by resource contention. In order to understand and avoid such situations, we investigate the impact of(More)
Virtualization technology has been gaining acceptance in the scientific community due to its overall flexibility in running HPC applications. It has been reported that a specific class of applications is better suited to a particular type of virtualization scheme or implementation. For example, Xen has been shown to perform with little overhead for(More)
Grid technology enables access and sharing of data and computational resources across administrative domains. Thus, it is important to provide a uniform access and management mechanism couple with fine-grain usage policies for enforcing authorization. In this paper, we describe our work on enabling fine-grain access control for resource usage and(More)
As the technology for high-speed networks has evolved over the last decade, the interconnection of commodity computers (e.g., PCs and workstations) at gigabit rates has become a reality. However, the improved performance of high-speed networks has not been matched so far by a proportional improvement in the ability of the TCP/IP protocol stack. As a result(More)
A recent trend in modern high performance computing (HPC) system architectures employs " lean " compute nodes running a lightweight operating system (OS). Certain parts of the OS as well as other system software services are moved to service nodes in order to increase performance and scalability. This paper examines the impact of this HPC system(More)
Multi-core processors introduce many challenges both at the systemand application levels that need to be addressed in order to attain the best performance.In this paper, we study the impact of the multi-core technologies inthe context of two scalable, production-level molecular dynamics simulationframeworks. Experimental analysis and observations in this(More)