• KIPS Transactions on Computer and Communication Systems
• /
• v.9 no.9
• /
• pp.189-196
• /
• 2020

Recently, GPU cloud computing technology applying GPU(Graphics Processing Unit) devices to virtual machines is widely used in the cloud environment. In a cloud environment, GPU devices assigned to virtual machines can perform operations faster than CPUs through massively parallel processing, which can provide many benefits when operating high-performance computing services in a variety of fields in a cloud environment. In a cloud environment, a GPU device can help improve the performance of a virtual machine, but the virtual machine scheduler, which is based on the CPU usage time of a virtual machine, does not take into account GPU device usage time, affecting the performance of other virtual machines. In this paper, we test and analyze the performance degradation of other virtual machines due to the virtual machine that performs GPGPU(General-Purpose computing on Graphics Processing Units) task in the direct path based GPU virtualization environment, which is often used when assigning GPUs to virtual machines in cloud environments. Then to solve this problem, we propose a GPGPU task management method for a virtual machine.

• The KIPS Transactions:PartA
• /
• v.15A no.3
• /
• pp.167-180
• /
• 2008

Consolidating servers into a virtualized system increases entire system utilization, while suffers from performance degradation due to the additional virtualization layer. In this paper, we proposed a performance evaluation methodology for comparing virtualized systems with native non-virtualized systems. We defined a system waste rate per consolidated throughput as a metric, and described the method for calculating system waste rate and consolidated throughput for both of virtualized systems and non-virtualized systems. Using the proposing performance evaluation methodology, we established testbeds, evaluated their performance, and compared the metrics of both systems. As a result of the evaluation, we could show the appropriateness of our methodology and analyze the effect of the application characteristics.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.12 no.11
• /
• pp.5234-5251
• /
• 2018

It is well-known that virtualization technology can bring many benefits not only to users but also to service providers. From the view of system security and resource utility, higher resource sharing degree and higher system reliability can be obtained by the introduction of virtualization technology in distributed cloud. The small size time-sharing multiplexing technology which is based on virtual machine in distributed cloud platform can enhance the resource utilization effectively by server consolidation. In this paper, the concept of memory block and user satisfaction is redefined combined with user requirements. According to the unbalanced memory resource states and user preference requirements in multi-virtual machine environments, a model of proper memory resource allocation is proposed combined with memory block and user satisfaction, and at the same time a memory optimization allocation algorithm is proposed which is based on virtual memory block, makespan and user satisfaction under the premise of an orderly physical nodes states also. In the algorithm, a memory optimal problem can be transformed into a resource workload balance problem. All the virtual machine tasks are simulated in Cloudsim platform. And the experimental results show that the problem of virtual machine memory resource allocation can be solved flexibly and efficiently.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.14 no.4
• /
• pp.1520-1542
• /
• 2020

Traditional software testing typically uses many physical resources to manually build various test environments, resulting in high resource costs and long test time due to limited resources, especially for small enterprises. Cloud computing can provide sufficient low-cost virtual resources to alleviate these problems through the virtualization of physical resources. However, the provision of various test environments and services for implementing software testing rapidly and conveniently based on cloud computing is challenging. This paper proposes a multilayer cloud testing model based on cloud computing and implements a hybrid cloud testing system based on virtual machines (VMs) and networks. This system realizes the automatic and rapid creation of test environments and the remote use of test tools and test services. We conduct experiments on this system and evaluate its applicability in terms of the VM provision time, VM performance and virtual network performance. The experimental results demonstrate that the performance of the VMs and virtual networks is satisfactory and that this system can improve the test efficiency and reduce test costs through rapid virtual resource provision and convenient test services.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.21 no.4
• /
• pp.347-357
• /
• 2019

The usefulness of processing and analysis systems of GIS-based agricultural climate data is affected by the reliability and availability of computing infrastructures such as cloud, on-premises, and hybrid. Cloud technology has grown in popularity. However, various reference cases accumulated over the years of operational experiences point out important features that make on-premises technology compatible with cloud technology. Both cloud and on-premises technologies have their advantages and disadvantages in terms of operational time and cost, reliability, and security depending on cases of applications. In this study, we have described characteristics of four general computing platforms including cloud, on-premises with hardware-level virtualization, on-premises with operating system-level virtualization and hybrid environments, and compared them in terms of advantages and disadvantages when a huge amount of GIS-based agricultural climate data were stored and processed to provide public services of agro-meteorological and climate information at high spatial and temporal resolutions. It was found that migrating high-resolution agricultural climate data to public cloud would not be reasonable due to high cost for storing a large amount data that may be of no use in the future. Therefore, we recommended hybrid systems that the on-premises and the cloud environments are combined for data storage and backup systems that incur a major cost, and data analysis, processing and presentation that need operational flexibility, respectively.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.8 no.2
• /
• pp.709-722
• /
• 2014

In the $21^{st}$ century, IT reform has led to the development of cyber-infrastructure owing to the outstanding enhancement of computer and network performance. The ripple effect has continued to increase. Accordingly, this study suggests a new computational research environment using mobile devices. In order to simplify the access of supercomputer, Science AppStore, task management and virtualization technologies are developed on mobile devices. User can be able to research by utilizing computational science SW such as compressible flow solver and nano device simulation tool that in installed on supercomputer in mobile environments. Also, this research environment makes it possible to monitor the simulation result and covers 14 university, 33 subjects, and 1,202 individuals.

• Health Policy and Management
• /
• v.10 no.3
• /
• pp.68-87
• /
• 2000

This study aims at the operation of the hospice in the virtual space by the use of telecommunication technology. The hospice can be an efficient alternative for the elderly and terminal patients. It can achieve both the quality of life of patients and the conservations of medical resources. The virtualization creates new norms and values which are different from the conventional environments. The concepts and limitations which are crucial to the projection of the existing hospice into the virtual space are discussed. The items ranging from the hospice need to the design criteria of the modules are investigated. The most important point in constructing the virtual hospice center is the human factor, which characterizes the hospice. In addition, the real-world circumstances of the hospice should be considered in the realization of the VHC.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2019.10a
• /
• pp.113-114
• /
• 2019

클라우드 환경에서는 가상머신의 고성능 연산을 지원하기 위해 Graphic Processing Unit(GPU)를 사용한다. 가상머신들은 공평성을 위해 독립적인 가상머신 스케줄러를 사용하기 때문에 컴퓨팅 자원의 초과 사용으로 인한 성능 저하가 발생해도 동일한 작업을 수행하는 가상머신들의 성능은 균등하게 측정된다. 하지만 GPU 연산의 경우 다중 작업을 수행할 때 하드웨어 기반 스케줄러를 사용하며 가상머신의 입출력 작업을 위한 하이퍼바이저의 First In First Out(FIFO) 기반 스케줄링 기법으로 인해 가상머신 사이의 공평성을 보장할 수 없다. 본 논문에서는 GPU 메모리를 초과 사용하는 환경에서 가상머신들의 성능을 측정하고 성능 불균형으로 인한 문제를 분석한다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2013.05a
• /
• pp.86-87
• /
• 2013

최근 가상화 기술에 대한 많은 관심과 연구들로 인해 가상 머신은 물리(Native) 머신에 가까운 성능을 보이며 프로세서 및 메모리 자원을 제공하고 있다. 하지만 GPU 와 같은 그래픽 하드웨어에 대한 장치 가상화는 다른 가상화 기법에 비해 연구가 미흡한 상태로 가상화 환경에서의 영상처리에 걸림돌이 되고 있다. 가상화 환경에서의 영상처리는 기존의 X 윈도우 시스템을 이용하여 영상을 처리하는데, 이는 2D 영상처리에 최적화 되어 있어서 3D 영상을 처리하는데 성능의 한계 보일 뿐만 아니라 가상 머신에서 메모리가 중복으로 복사되면서 낮은 성능 보여주고 있다. 제안하는 장치 가상화 프레임워크는 기존의 메모리의 중복 복사를 제거하면서 성능을 향상 시킬 수 있다. 본 논문에서는 가상화 환경에서 GPU 성능 향상을 위한 장치 가상화 프레임워크를 제안하고 평가를 통해 본 기법의 타당성을 입증한다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2010.11a
• /
• pp.1822-1825
• /
• 2010

기업의 데이터 센터의 규모가 커지면서 서버 가상화가 중요한 이슈가 되고 있다. 하지만, 서버의 효율성을 높이기 위해 제안된 가상화 환경의 특징은 가상 머신 내부에서 실제 시스템 사용률을 측정하는데 어려움을 초래했다. 이는 외부에서 가상 머신이 동작중인 물리 머신의 부하를 잘못 인식하게 만들며, 기존 로드 밸런싱 기법 적용의 효율성을 저하시킨다. 이러한 문제를 해결하기 위해 본 논문에서는 가상 머신의 I/O 요청의 총량에 기반을 둔 로드 밸런싱 기법을 제안한다. 제안하는 기법에서 로드밸런싱 서버는 각각의 물리 서버의 I/O 처리량의 한계값을 알고 있으며, 한계값보다 낮은 I/O 요청이 있는 물리 서버에 속한 가상 머신에게만 작업을 분배한다.