• Journal of KIISE:Computer Systems and Theory
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• v.34 no.9
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• pp.407-415
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• 2007

In parallel cluster computing systems, the efficiency of communication between computing nodes is one of important factors that decide overall system performance. Accordingly, many researchers have studied on high-performance inter-node communication. The recently launched multi-core processor, however. increases the importance of intra-node communication as well because the more the number of cores in a node, the more the number of parallel processes running in the same node. Though there have been studies on intra-node communications, these have limited considerations on the state-of-the-art systems. In this paper, we propose a Linux kernel module that minimizes the number of data copy by exploiting the memory mapping mechanism for high-performance intra-node communication. The proposed kernel module supports the Linux kernel version 2.6. The performance measurements over a multi-core system present that the proposed kernel module can achieve lower latency up to 62% and higher throughput up to 144% than an existing kernel module approach. In addition, the measurements reveal that the performance of intra-node communication can vary significantly based on whether the cores that run the communication processes are belong to the same processor package (i.e., sharing the L2 cache).

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.5
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• pp.539-548
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• 2015

In this paper, shared memory feature was developed in multi-core system with different OS for different processor-specific bus, while conducting an experiment on shared memory feature between the two processors based on embedded Linux system. For the purpose of developing shared memory in dual bus structure, memory controller was used, while managing shared memory segment through list data structure. For AMP multi-core test, Linux OS was installed in 2 processor cores. In addition, it verified the creation and use of shared memory by using kernel module implemented to test shared memory.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.100-102
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• 2001

Intensive I/O bandwidth demand of the multimedia streaming service puts significant burden on file system. Different from the legacy text based or image data, the semantics of the data in multimedia format can be significantly affected if the data block is not delivered by the predefined deadline. The legacy file system used in Unix or Unix like environment is designed to efficiently handle the files who sizes range from few hundreds of byte to several tens of gigabytes. This fundamental design philosophy results in the file system based on multi level skewed tree structure. Multi level i-node structure has significant drawback when the application performs sequential read operation. In this article, we present the result of the performance study of the file system which is specifically designed for handling multimedia streams. We implemented the file system on Linux Operating System environment and examines the performance behavior of the file system under streaming I/O workload. The result of the study shows that the proposed file system performs much more efficiently than the ext2 file system of Linux does.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.12
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• pp.968-972
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• 2009

The multi-core processors are being widely exploited by many high-end systems. With significant advances in processor architecture, the network band-width required on the high-end systems is increasing drastically. It is therefore highly desirable to manage multiple cores efficiently to achieve high network band-width with minimum resource requirements. Modern operating systems, however, still have significant design and optimization space to leverage the network performance over multi-core systems. In this paper, we suggest a novel networking process scheduling scheme, which decides the best processor affinity of networking processes based on the processor cache layout, communication intensiveness, and processor loads. The experimental results show that the scheduling scheme implemented in the Linux kernel can improve the network bandwidth and the effectiveness of processor utilization by 20% and 59%, respectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.65-67
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• 2013

The recent high-performance network equipment is required, and also require high network bandwidth utilization. It is a trend to develop increasingly using multi-core processors for high-performance network servers. Propose a method to improve the performance of the network sub-system, considering the characteristics of multi-core as a way to improve these high-performance and high network throughput. In this paper, we confirm through experiments on how to improve the communication performance, optimize performance and take full advantage of multi-core by Network communication process to improve the performance of the multi-core processor architecture, the process of concentration, the overhead for each core, based on network traffic according to the interrupt affinity in this process to determine the optimal core to give. The experiments were implemented in the Linux kernel, and experiments to improve the network throughput up to 30%, bringing reduces the Linux communication process to improve the performance of the processor overhead of up to 10%.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.215-220
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• 2005

Nowadays, various speech processing systems are being introduced in the fields of robotics. However, real-time processing and high performances are required to properly implement speech processing system for the autonomous robots. Achieving these goals requires advanced hardware techniques including intelligent software algorithms. For example, we need nonlinear amplifier boards which are able to adjust the compression radio (CR) via computer programming. And the necessity for noise reduction, double-buffering on EPLD (Erasable programmable logic device), simultaneous multi-channel AD conversion, distant sound localization will be explained in this paper. These ideas can be used to improve distant and omni-directional speech recognition. This speech processing system, based on embedded Linux system, is supposed to be mounted on the new home service robot, which is being developed at KIST (Korea Institute of Science and Technology)

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.148-151
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• 2001

We suggest AKL(abstract kernel layer) to. the design and implementation of WAP on basis of multi-platform. AKL is running on the various kernel including REX, MS-DOS, MS-Windows, UNIX and LINUX. For the purpose of it, AKL makes machine-dependant features be minimized and supports a consistent interface on API(application program interface) point of views. Therefore, It makes porting times of a device be shorten and makes easy of maintenance. We validated our suggestion as a consequent of porting WAP into PalmV PDA and mobile phone with AKL.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.279-282
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• 2002

초고속 통신망이 발달함에 따라 대기업은 물론, 학교와 중소기업에도 네트워크로 연결되어 업무 및 학습과 행정업무를 처리하고 있다. 인터넷을 이용한 재택근무, 재택교육 등이 발달하고 있는 시점에서 안정적이고 효율적인 네트워크환경을 제공하기 위해서는 네트워크상에 존재하는 다양한 자원들을 모니터링하고 제어하는 네트워크의 관리의 개념이 필요하게 되었다. 하지만, 대부분의 기업체나 학교에서는 구축비용측면에서 이를 투자하기를 꺼려하고 있다. 이에 본 논문에서는 중소기업 및 학교업무에서 일반적으로 사용되고 있는 MRTG(Multi Graphic Rotor Grapher)를 연계하여 웹을 이용한 손쉽게 망을 관리할 수 있는 툴을 perl을 이용하여 구현하였다. 장애의 대부분이 네트웍 자원관리와 실시간 로그관리를 이용할 경우 대부분의 장애를 미연에 방지할 수 있다는 점에 착안하여 텍스트를 처리함에 있는 탁월한 기능을 가진 perl을 이용하여 로그처리 데몬프로그램을 작성하였고, 자원관리와 이력관리를 위해서는 MySQL을 이용하였다.

• The Journal of the Korea Contents Association
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• v.17 no.10
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• pp.587-597
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• 2017

Recently, the demand for real-time performance in mobile environment is increasing due to the improvement of hardware performance, however a GPOS(General-Purpose Operating System) such as Android and Linux do not provide real-time performance. We developed RTiK(Real-Time implant Kernel) for this problem, but it has the disadvantage of supporting only x86 Architecture. In this paper, we designed and implemented a RTiKA(Real-Time implanted Kernel for ARM) to support real-time in ARM Linux. We used MCT(Multi-Core Timer) timer which replaces Local APIC Timer for real-time support, and we measured the period of generated real-time task for performance verification and evaluation. As the recent the RTiKA can guarantee the operating of several real-time tasks based on the cycle of 1ms.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.12
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• pp.2341-2347
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• 2016

In this paper, we implement monitoring system for grain sorting using a high-speed FPGA and embedded LINUX. The proposed system is designed by base on web server and web-based applications while existing system was designed by base on stand-alone mode.The interface the Web server with high speed hardware of FPGA is designed on the implemented monitoring system. The proposed system has the advantages of multi-tasking on Linux web server and real-time high speed on FPGA also. The control logic of a high speed rate line-scan CCD camera, the method of center of gravity, HSL decoding and the interface on the Web server are implemented in FPGA. The implemented monitoring system has the advantage of being able to control the grain monitoring, system failure and recovery remotely by web application. As a result, we can upgrade the performance of sorting quality compared by existing system.