• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.14 no.3
• /
• pp.163-169
• /
• 2014

Recently, the importance of multicore processor system is growing rapidly. Multicore processors are classified either as symmetric or asymmetric. Asymmetric multicore processors consist of a high performance complex core and number of low performance simple cores, and are known to be more efficient than symmetric multicore processors. Therefore, performance impact on various configurations of asymmetric multi-core processor needs to be studied. Using SPEC 2000 benchmarks as input, the trace-driven simulation has been performed for different asymmetric quad-core and octa-core processors and compared to the corresponding symmetric ones.

• Journal of the Korea Society of Computer and Information
• /
• v.17 no.6
• /
• pp.1-11
• /
• 2012

As the process technology scales down, multi-core processors cause serious problems such as increased interconnection delay, high power consumption and thermal problems. To solve the problems in 2D multi-core processors, researchers have focused on the 3D multi-core processor architecture. Compared to the 2D multi-core processor, the 3D multi-core processor decreases interconnection delay by reducing wire length significantly, since each core on different layers is connected using vertical through-silicon via(TSV). However, the power density in the 3D multi-core processor is increased dramatically compared to that in the 2D multi-core processor, because multiple cores are stacked vertically. Unfortunately, increased power density causes thermal problems, resulting in high cooling cost, negative impact on the reliability. Therefore, temperature should be considered together with performance in designing 3D multi-core processors. In this work, we analyze the temperature of the cache in quad-core processors varying cache organization. Then, we propose the low-temperature cache organization to overcome the thermal problems. Our evaluation shows that peak temperature of the instruction cache is lower than threshold. The peak temperature of the data cache is higher than threshold when the cache is composed of many ways. According to the results, our proposed cache organization not only efficiently reduces the peak temperature but also reduces the performance degradation for 3D quad-core processors.

• Proceedings of the Korean Information Science Society Conference
• /
• 2011.06b
• /
• pp.450-453
• /
• 2011

반도체 공정 기술의 발달에 따라 프로세서의 성능은 비약적으로 증가하였다. 특히 최근에는 하나의 프로세서에 여러 개의 코어를 집적한 멀티코어 프로세서 기술이 급속도로 발달하고 있는 추세이다. 멀티코어 프로세서는 동작주파수를 높여 성능을 개선하는 싱글코어 프로세서의 한계를 극복하기 위해 코어 개수를 늘림으로써 각각의 코어가 더 낮은 동작주파수에서 실행할 수 있도록 하여 소모 전력을 줄일 수 있다. 또한 다수의 코어가 동시에 연산을 수행하기 때문에 싱글코어 프로세서보다 더 많은 연산을 효율적으로 수행하여 사용률이 크게 높아지고 있지만 멀티코어 프로세서에서는 다수의 코어를 단일 칩에 집적하였기 때문에 전력밀도의 증가와 높은 발열이 문제가 되고 있다. 이와 같은 상황에서 본 논문에서는 듀얼코어 프로세서를 탑재한 시스템과 쿼드코어 프로세서를 탑재한 시스템의 소모 전력과 온도를 실제 측정하고 시뮬레이션을 통해 얻은 가상 시스템의 결과를 비교, 분석함으로써 실제 측정 결과와 시뮬레이션 결과가 얼마나 유사한지를 살펴보고, 차이가 발생하는 원인에 대한 분석을 수행하고자 한다. 실험결과, 실제 시스템을 측정한 결과와 시뮬레이션을 통한 가상 시스템의 결과는 매우 유사한 추이를 보이는 것으로 나타났다. 하지만 실제 시스템의 소모 전력과 온도의 증가비율은 가상 시스템의 소모 전력과 온도의 증가비율과는 다른 경향을 보이는 것을 확인하였다.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.15 no.5
• /
• pp.219-224
• /
• 2015

Recently, the multi-core processor architecture is widely used in the digital signal processors for enhancing its performance. Multi-core processors are classified either as symmetric or asymmetric. Asymmetric multi-core processors are known to have higher performance and more efficient than symmetric multi-core processors. In order to study the performance enhancement of asymmetric multi-core digital signal processors over the symmetric ones, the trace-driven simulation has been executed for various asymmetric quad-core, octa-core and hexadeca-core digital signal processors and compared with the symmetric ones of similar hardware budget using UTDSP benchmarks as input.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.16 no.1
• /
• pp.233-238
• /
• 2016

Recently, the multi-core processor architecture is widely adopted in the embedded processors for enhancing its performance. Multi-core processors are classified either as symmetric or asymmetric. Asymmetric multicore processors are known to score higher performance and more efficient than symmetric multi-core processors. In order to study the performance enhancement of asymmetric multi-core embedded processors over the symmetric ones, the trace-driven simulation has been executed for various asymmetric embedded dual-core, quad-core, octa-core and hexadeca-core processors and compared with the symmetric ones of similar hardware budget using MiBench benchmarks as input.

• The Magazine of the IEIE
• /
• v.43 no.7
• /
• pp.25-32
• /
• 2016

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2010.07a
• /
• pp.252-255
• /
• 2010

고해상도의 동영상 서비스가 보편화 되면서 동영상을 빠르게 처리를 위한 연구가 활발히 이루어 지고 있다. 그리고 멀티코어 프로세서의 사용이 증가 하고 멀티코어 시스템에서 H.264/AVC 디코더를 구현하기 위하여 다양한 병렬화 방법이 제안되고 있다. 하지만 H.264/AVC디코더의 병렬화를 진행하는 과정에서 각 스레드에서 처리하는 데이터의 처리시간 차이로 인하여 스레드의 동기를 확인 해야 한다. 이로 인하여 병렬화를 통한 성능 향상의 걸림돌이 된다. 우리는 이러한 병렬화 과정에서 발생하는 문제점을 고려하여 효과적으로 H.264/AVC 디코더를 병렬화 하는 방법에 대하여 연구하였다. 우리가 제안하는 Frame Partition based Parallelization (FPP) 방법은 프레임을 매크로 블록 묶음으로 나누어 병렬화 한다. 그리고 병렬화 과정에서 스레드를 처리하는 방법을 개선하여 성능을 향상 시켰다. 본 논문에서는 FFmpeg H.264/AVC 디코더를 이용하여 실험 하였고 인텔 쿼드 코어 기반의 멀티코어 시스템에서 멀티 스레드로 구현하였다. 우리는 FPP 방법을 적용하여 병렬화 방법 적용 전 H.264/AVC 디코더와 비교하여 최대 53%의 성능 향상을 보였다.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.14 no.1
• /
• pp.138-144
• /
• 2010

Tachyon primary system which introduces recently is a high performance supercomputer that composed with AMD Barcelona nodes. In this paper, we will verify the performance and parallel scalability of TachyonIn by using multi-zone NAS Parallel Benchmark(NPB) which is one of a program with hybrid parallel method. To test performance of hybrid parallel execution, B and C classes of BT-MZ in NPB version 3.3 were used. And the parallel scalability test has finished with Tachyon's 1024 processes. It is the first time in Korea to get a result of hybrid parallel computing calculation using more than 1024 processes. Hybrid parallel method in high performance computing system with multi-core technology like Tachyon describes that it can be very efficient and useful parallel performance benchmarks.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.47 no.11
• /
• pp.43-53
• /
• 2010

Wide deployment of high resolution video services leads to active studies on high speed video processing. Especially, prevalent employment of multi-core systems accelerates researches on high resolution video processing based on parallelization of multimedia software. In this paper, we propose a novel parallel H.264/AVC decoding scheme on a multi-core platform. Parallel H.264/AVC decoding is challenging not only because parallelization may incur significant synchronization overhead but also because software may have complicated dependencies. To overcome such issues, we propose a novel approach called Multi-Threaded Parallelization(MTP). In MTP, to reduce synchronization overhead, a separate thread is allocated to each stage in the pipeline. In addition, an efficient memory reuse technique is used to reduce the memory requirement. To verify the effectiveness of the proposed approach, we parallelized FFmpeg H.264/AVC decoder with the proposed technique using OpenMP, and carried out experiments on an Intel Quad-Core platform. The proposed design performs better than FFmpeg H.264/AVC decoder before the parallelization by 53%. We also reduced the amount of memory usage by 65% and 81% for a high-definition(HD) and a full high-definition(FHD) video, respectively compared with that of popular existing method called 2Dwave.