Kejiang Ye | Carnegie Mellon University (original) (raw)

Papers by Kejiang Ye

IEEE Transactions on Parallel and Distributed Systems, 2014

Improving energy efficiency of data centers has become increasingly important nowadays due to the... more Improving energy efficiency of data centers has become increasingly important nowadays due to the significant amounts of power needed to operate these centers. An important method for achieving energy efficiency is server consolidation supported by virtualization. However, server consolidation may incur significant degradation to workload performance due to virtual machine (VM) co-location and migration. How to reduce such performance degradation becomes a critical issue to address. In this paper, we propose a profiling-based server consolidation framework which minimizes the number of physical machines (PMs) used in data centers while maintaining satisfactory performance of various workloads. Inside this framework, we first profile the performance losses of various workloads under two situations: running in co-location and experiencing migrations. We then design two modules: (1) consolidation planning module which, given a set of workloads, minimizes the number of PMs by an integer programming model, and (2) migration planning module which, given a source VM placement scenario and a target VM placement scenario, minimizes the number of VM migrations by a polynomial time algorithm. Also, based on the workload performance profiles, both modules can guarantee the performance losses of various workloads below configurable thresholds. Our experiments for workload profiling are conducted with real data center workloads and our experiments on our two modules validate the integer programming model and the polynomial time algorithm.

IEEE Internet Computing, May 20, 2014

Modern cloud computing environments often use virtualization technology to implement resource sha... more Modern cloud computing environments often use virtualization technology to implement resource sharing. However, virtualization incurs performance overheads due to the additional hypervisor layer placed between virtual machines (VMs) and hardware resources. Understanding VM performance is crucial for running applications efficiently and for further improving VM techniques. Unfortunately, existing benchmarking methods are insufficient for comprehensively measuring virtualization performance. Here, the authors propose a solution that fully evaluates VM system performance. In addition to discussing their three-layer benchmarking methodology, they present a new benchmark suite -- Virt-B -- that measures various virtualization scenarios. They also introduce a performance testing toolkit to automate the benchmarking process and describe three case studies.

The Third International Conference on Cloud Computing, GRIDs, and Virtualization (CLOUD COMPUTING 2012), 2012

Abstract: Live migration is a widely used technology for load balancing, fault tolerance, and pow... more Abstract: Live migration is a widely used technology for load balancing, fault tolerance, and power saving in cloud data centers. Previous research includes significant research work in the performance improvement of live migration. However, little work has been done to investigate the influence of live migration on virtual machine workloads that users care about most. We notice that these workloads can be classified into two categories: single-tier workloads and multi-tier workloads which is a typical type for internet applications.

2012 IEEE International Conference on Cluster Computing Workshops (IEEE Cluster 2012 Workshops)

2012 ACM/IEEE 13th International Conference on Grid Computing (GRID),

International Journal of Numerical Analysis and Modeling

ACM SIGMETRICS Performance …, Jan 1, 2011

Abstract Virtualization technology has been widely applied in data centers and IT infrastructures... more Abstract Virtualization technology has been widely applied in data centers and IT infrastructures, with advantages of server consolidation and live migration. Through live migration, data centers could flexibly move virtual machines among different physical machines to balance workloads, reduce energy consumption and enhance service availability. Today&#x27;s data centers can grow to a huge scale. This implies that frequent live migration would be desirable for the economic use of hardware resources. Then, the ...

Cluster Computing (CLUSTER), 2011 …, Jan 1, 2011

Cloud computing has recently received considerable attention. With the fast development of cloud ... more Cloud computing has recently received considerable attention. With the fast development of cloud computing, the data center is becoming larger in scale and consumes more energy. There is an emergency need to develop efficient energy-saving methods to reduce the huge energy consumption in the cloud data center. In this paper, we achieve this goal by dynamically allocating resources based on utilization analysis and prediction. We use "Linear Predicting Method" (LPM) and "Flat Period Reservation-Reduced Method" (FPRRM) to get useful information from the resource utilization log, and make M/M/1 queuing theory predicting method have better response time and less energy-consuming. Experimental evaluation performed on CloudSim cloud simulator shows that the proposed methods can effectively reduce the violation rate and energy-consuming in the cloud.

… of the second joint WOSP/SIPEW …, Jan 1, 2011

Virtualization technology has been widely applied in data centers and IT infrastructures, with ad... more Virtualization technology has been widely applied in data centers and IT infrastructures, with advantages of server consolidation and live migration. Through live migration, data centers could flexibly move virtual machines among different physical machines to balance workloads, reduce energy consumption and enhance service availability.

Today's data centers can grow to a huge scale. This implies that frequent live migration would be desirable for the economic use of hardware resources. Then, the performance of the live migration strategy will be an issue. So, we need a reliant evaluation method to choose the software and hardware environments that will produce the best live migration performance.

However, there is not a complete live migration benchmark available currently. In addition, the existing evaluation methodologies select different metrics, different workloads and different test means. Thus, it is difficult to compare their results.

In this paper we first survey the current research and their evaluation methods on live migration. We then summarize the critical issues for the live migration evaluation and also raise other unreported potential problems.

We propose our solutions and present an implementation in our live migration benchmark -- Virt-LM. This is a benchmark for comparing live migration performance among different software and hardware environments in a data center scenario. We detail its design and provide some experimental results to validate its effectiveness.

2010 IEEE/ACM International Conference on Green Computing and Communications (GreenCom'2010), Jan 1, 2010

Virtual machine technology is widely applied to modern data center for cloud computing as a key t... more Virtual machine technology is widely applied to modern data center for cloud computing as a key technology to realize energy-efficient operation of servers. Server consolidation achieves energy efficiency by enabling multiple instantiations of operating systems (OSes) to run simultaneously on a single physical machine. While, live migration of virtual machine can transfer the virtual machine workload from one physical machine to another without interrupting service. However, both the two technologies have their own performance overheads. There is a tradeoff between the performance and energy efficiency. In this paper, we study the energy efficiency from the performance perspective. Firstly, we present a virtual machine based energy-efficient data center architecture for cloud computing. Then we investigate the potential performance overheads caused by server consolidation and live migration of virtual machine technology. Experimental results show that both the two technologies can effectively implement energy-saving goals with little performance overheads. Efficient consolidation and migration strategies can improve the energy efficiency.

2010 12th IEEE International Conference on High Performance Computing and Communication (HPCC), Jan 1, 2010

Virtualization technology is currently widely used due to its benefits on high resource utilizati... more Virtualization technology is currently widely used due to its benefits on high resource utilization, flexible manageability and powerful system security. However, its use for high performance computing (HPC) is still not popular due to the unclearness of the virtualization overheads. It's worthy to evaluate the virtualization cost and to find the performance bottleneck when running HPC applications in virtual cluster. We first evaluate the basic performance overheads due to virtualization. Then we create a 16-node virtual cluster and perform a performance evaluation for both para-virtualization and full virtualization. After that, we evaluate the MPI (Message Passing Interface) scalability to investigate the impact of MPI and network communication between virtual machines. In addition to the macro assessment, we use the Oprofile/Xenoprof to investigate the architecture characterization like CPU cycle, L2 cache misses, DTLB misses and ITLB misses which is an auxiliary explanation to the performance bottleneck. Experimental results indicate that performance overheads of virtualization are acceptable for HPC, para-virtualization is very suitable for HPC due to the high virtualization efficiency and efficient inter-domain communication. Finally, we use the non-linear regression modeling technology to present a performance model for network latency and bandwidth to predict the performance in virtual cluster environment.

2011 IEEE International Conference on Cloud Computing (CLOUD), Jan 1, 2011

Virtualization technology is currently becoming increasingly popular and valuable in cloud comput... more Virtualization technology is currently becoming increasingly popular and valuable in cloud computing environments due to the benefits of server consolidation, live migration, and resource isolation. Live migration of virtual machines can be used to implement energy saving and load balancing in cloud data center. However, to our knowledge, most of the previous work concentrated on the implementation of migration technology itself while didn't consider the impact of resource reservation strategy on migration efficiency. This paper focuses on the live migration strategy of multiple virtual machines with different resource reservation methods. We first describe the live migration framework of multiple virtual machines with resource reservation technology. Then we perform a series of experiments to investigate the impacts of different resource reservation methods on the performance of live migration in both source machine and target machine. Additionally, we analyze the efficiency of parallel migration strategy and workload-aware migration strategy. The metrics such as downtime, total migration time, and workload performance overheads are measured. Experiments reveal some new discovery of live migration of multiple virtual machines. Based on the observed results, we present corresponding optimization methods to improve the migration efficiency.

2010 IEEE 12th International Conference on High Performance Computing and Communications (HPCC), Jan 1, 2010

Virtualization brings many benefits such as improving system utilization and reducing cost throug... more Virtualization brings many benefits such as improving system utilization and reducing cost through server consolidation. However, it also introduces isolation problem when running multiple virtual machine workloads in one physical platform. Additionally, with the advent of multi-core technology, more and more cores are built into one die in today's data center that will share and compete for the resource like cache. It's worthy to study the isolation of server consolidation in modern multi-core platform. However, to our knowledge there are few work done on the isolation property especially the fault isolation property when one of the virtual machine workloads is attacked in server consolidation. In this paper, we study the isolation property from performance perspective and provide two optimization methods to improve the isolation property. We first define the isolation property and quantify the performance isolation in consolidation and propose a VM-level optimization method. Then we study the fault isolation by introducing a misbehavior virtual machine in server consolidation scenario and propose a core-level cache-aware optimization method to improve the fault isolation. Experimental results show that our two optimization methods can effectively improve the performance isolation and fault isolation with 29.39% and 19.52% respectively. What's more, Oprofile/Xenoprof toolkits are used to find out the factors affecting isolation property from the hardware events level.

… (ChinaGrid), 2010 Fifth …, Jan 1, 2010

Virtualization technology has attracted wide attention in recent years as a method to improve res... more Virtualization technology has attracted wide attention in recent years as a method to improve resource utilization, reduce costs, and ease server management. However, the performance penalty resulting from virtualization is an unneglectable problem and should be carefully evaluated. To our knowledge, there are few performance evaluating tools developed for virtualization environments. We propose a configurable framework and implement a prototype vTestkit to provide a platform to do performance evaluation for virtualization environments easily, flexibly, and automatically. In this paper, we first discuss the requirements and challenges of performance measurement in virtualization environments, and then present a methodology for characterizing the performance of single virtual machine (VM) scenario and multi-VM scenario. Then we introduce the architecture of vTestkit framework, implement details, and the testing process with vTestkit. Finally, three typical case studies are presented to show that vTestkit can meet the complex testing requirements well and is propitious to various scenarios.

2010 IFIP International Conference on Network and Parallel Computing (NPC'2010), Lecture Notes in Computer Science, Volume 6289, 2010, Jan 1, 2010

Virtualization technology plays an important role in modern data center, as it creates an opportu... more Virtualization technology plays an important role in modern data center, as it creates an opportunity to improve resource utilization, reduce energy costs, and ease server management. However, virtual machine deployment issues arise when allocating virtual machines into single or multiple physical servers. In this paper, we explore the performance and scalability issues for virtual machine deployment in a virtualized data center. We first evaluate the image scalability when allocating multiple VMs per physical server using four typical servers in data center. Then we investigate how the overall efficiency will be affected when deploying M virtual machines into N physical machines with different deployment strategies. Experimental results show that: (i) There is a resource bottleneck when deploying single type virtual machine server into single physical server, except for composite workloads. (ii) More physical machines do not always benefit for some specific applications to support a fixed number of virtual machines. (iii) MPI and network communication overheads affect the deployment efficiency seriously.