• KIPS Transactions on Computer and Communication Systems
• /
• v.6 no.12
• /
• pp.469-478
• /
• 2017

The mutual exclusion is originally based on the theory of race condition prevention in symmetric multi-processor operating systems. But recently, due to the generalization of multi-core processors, its application range has been rapidly shifted to parallel processing application domain. POSIX thread, WIN32 thread, and Java thread, which are typical parallel processing application development environments, provide a unique mutual exclusion mechanism for each of them. Applications that are very sensitive to performance in these environments may want to reduce the burden of mutual exclusion, even at some cost, such as inconvenience of coding. In this study, we implement Dekker's and Peterson's algorithm in the form of busy-wait and processor-yield in various platforms, and compare the performance of them with the built-in mutual exclusion mechanisms to evaluate the usability of the classic algorithms. The analysis result shows that Dekker's algorithm of processor-yield type is superior to the built-in mechanisms in POSIX and WIN32 thread environments at least 2 times and up to 70 times, and confirms that the practicality of the algorithm is sufficient.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.6 no.4
• /
• pp.216-223
• /
• 2013

As the fast growth of using Internet, the requests of clients having different types and pressing loads on the server have been increased in World Wide Web. Thus the interesting issue is how to measure the real capacity of a Web Server. There have been much recent studies about measuring the capacity of web server. But the cause of Server response time delay is not just server itself but also network packet loss. To measure the practical capacity of web server, we generate scalable clients using Posix Thread, transport packets which were generated by scalable clients to the server using UDP and receive the packets which were the remain packet from network packet loss using TCP. In this paper, we propose a method to measure the practical capacity of a web server using the Scalable Clients based on Posix Thread and the transport on Application level.

• Proceedings of the Korean Information Science Society Conference
• /
• 1999.10c
• /
• pp.759-761
• /
• 1999

본 논문에서는 동적 병렬 태스크를 추출하는 메커니즘을 공유 메모리 구조상에서 구현하는데 있어서 최적화 기법에 대해서 소개한다. 최대의 호환성을 고려하여 POSIX thread와 C언어를 사용하였는데 이에 따른 오버헤드를 여러 가지 구현 기법을 사용하여 줄이고자 노력하였다. 그리고 병렬 처리시 대부분의 계산은 각 처리기에서 순차 계산에 의해 이루어지므로 이 순차 계산시에 발생하는 오버헤드를 줄이는 것을 최우선으로 하였다.

• The KIPS Transactions:PartA
• /
• v.9A no.2
• /
• pp.249-258
• /
• 2002

One of the jai or purposes of multiprocessor system is to get a high efficiency in performance improvement. But in most cases, it is unavoidable to use some special programming languages or tools for full use of multiprocessor system. In general, loop and recursive call statements of algorithms are considered as typical parts for parallelization. Especially, recursive call statements are easy to parallelize conceptually without support of any special languages or tools. But it is difficult to control the degree of parallelism caused by high depth of recursive call leading to execution crash. This paper proposes a device to control Parallelism in the process of POSIX thread bated parallelization of recursive algorithms. For this, we define the concept of thread and process in UNIX system, and analyze the results of experimental application of the device to quick sorting algorithm.

• Proceedings of the Korean Information Science Society Conference
• /
• 1998.10a
• /
• pp.160-162
• /
• 1998

본 논문은 실시간 운영체계인 ARX 의 독특한 메커니즘을 바탕으로 한 POSIX 의 thread library( Pthread library)의 구현에 대하여 다룬다. ARX Pthread library는 POSIX 1003.lc의 규약을 따르며 실시간 프로그램밍의 특성에 맞도록 이를 확장한 주기적인 thread, deadine handler등의 확장된 인터페이스를 제공한다. 이와 더불어 정확한 실시간 특성을 제공하기 위하여 사용자 수준 타이머의 관리도 제공하고 있다. 한편 ARX 의 핵심인 가살쓰레드와 개선된 스케줄링 이벤트 업콜 방식을 바탕으로 사용자 수준 쓰레드와 사용자 수준 스케줄러의 동기화를 제공하는 사용자 수준 동기화 도구를 구현하였다. 이러한 Pthread library를 사용한 응용프로그램의 timing anlysis의 결과는 ARX 의 뛰어난 실시간 처리 능력과 함께 다양한 실시간 응용 프로그램의 요구를 수용할 수 있음을 보여준다.

• Journal of Digital Convergence
• /
• v.13 no.12
• /
• pp.381-390
• /
• 2015

One of the fundamental requirements of entertainment applications is interactivity with users. The mobile device such as the smartphone, however, does not guarantee it due to the limit of the application processor's computing power, memory size and available electric power of the battery. This paper proposes a methodology to boost responsiveness of interactive applications by taking advantage of the parallel architecture of mobile devices which, for instance, have dual-core, quad-core or octa-core. To harness the multi-core architecture, it exploits the POSIX thread, a platform-independent thread library to be able to be used in various mobile platforms such as Android, iOS, etc. As a useful application example of the methodology, a heavy matrix calculation function was transformed to a parallelized version which showed around 2.5 ~ 3 times faster than the original version in a real-world usage environment.

• Proceedings of the Korean Information Science Society Conference
• /
• 2007.10b
• /
• pp.414-418
• /
• 2007

멀티프로세서 환경에서 OpenMP는 MPI 에 비해 병렬 프로그래밍을 쉽게 할 수 있다는 장점을 가지고 있고, OpenMP는 표준이 없는 병렬 프로그래밍 세계에서 실질적인 표준으로써 인정받고 있다. OPenMP는 대상 플랫폼에 따라 OpenMP 구현을 다르게 해야 하기 때문에 새로운 프로세서가 등장하면 그에 맞는 OpenMP구현을 만들어야 한다. 이 논문에선 다중 프로세서 시스템-온-칩 시스템인 ARM11MPCore 시스템 위에 POSIX 쓰레드에 기반하여 OpenMP 환경을 구축하고 그 성능을 측정한다.

• The Transactions of the Korea Information Processing Society
• /
• v.4 no.4
• /
• pp.1106-1120
• /
• 1997

In this paper,we prosent a new run-time support system for SR usitn POSIX threads (Pthreads),called SR/RTS +.SR supports a rich set of concurent programming techniques with multiple cincurrency control primit-ives Since the original RTS for SR uses its own thread management facility,it should be modifide to work on different computer systems.Furthermore,the run-time efficiency of the RTS should be considered in association with those different sytems.Thus,to portability and to guarantee the predictable run-time ef-ficiency,SR/RTS + is designed on the pthreads(POSIX Threads )which supports multiple threads of con-trol within a single POSIX process.Also, the SR compiler is modified to generate the codes appropriate for pthreads interface.SR/RTS + has been develped on Spare Workstation using pthreads library announced by Florida State University and tested with the SR verification suite distribute by the University of Arizona.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2012.11a
• /
• pp.219-222
• /
• 2012

최근 얼굴검출에 관한 연구는 FPGA를 통한 H/W설계부터 DSP, GPU, ARM Core에 효율적인 S/W 설계까지 다양하게 연구되고 있다. 본 연구에서는 Multi-Core에 효과적인 얼굴검출 방법을 제안한다. 피부색을 통한 얼굴 후보를 추출하고 그 외의 배경 이미지는 삭제하여 연산처리를 빠르게 하였다. Viola-Jones가 제안한 얼굴검출 알고리즘을 POSIX Thread를 사용하여 병렬 처리하였고 그 성능을 단일 코어와 멀티코어에서 측정하였다. 단일 코어에서는 성능의 향상이 없었으나 멀티코어에서는 약 1.8배 속도가 향상되었고 검출 성공률은 기존과 동일하였다.