• 한국정보처리학회논문지
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• 제7권3호
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• pp.962-970
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• 2000

Multithreading is attractive in that it can tolerate memory latency and synchronization by effectively overlapping communication with computation. While several compiler techniques have been developed to produce multithreaded codes from functional languages programs, there still remains a lot of works to implement loops effectively. Executing lops in a style of multithreading usually causes some overheads, which can reduce severely the effect of multirheading. This paper suggests several methods in terms of architectures or compilers which can optimize loop execution by multithreading. We then simulate and analyze them for the matrix multiplication program.

• 한국정보과학회논문지:소프트웨어및응용
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• 제29권11호
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• pp.826-836
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• 2002

Id 언어와 같은 함수형 언어의 중천루프에 포함된 미세한 수준의 대규모 병렬성을 다중스레드 구조상에서 이용하려면 프로세서뿐만 아니라, 이름공간을 위한 상당히 말은 기억공간 등의 자원이 추가로 요구된다. 이러한 병렬성을 포함하는 중첩루프론 시스템 자원 제한 없이 무분별하게 펼쳐서 실행하려고 한다면, 실행도중 기억공간의 자원의 고갈로 인하여 프로그램의 실행이 중단될 수 있다. 또한, 루프의 펼침에 따른 부담으로 인하여 프로세서의 수에 비해서 루프를 지나치게 많이 펼치는 경우에, 병렬 수행의 효과가 상당히 떨어질 수 있다. 본 논문에서는 함수형 언어의 중첩루프를 다중스레드 구조상에서 효과적으로 펼쳐서 실행할 수 있는 알고리즘을 제안하고 분석한다. 제안된 알고리즘의 특성은 주어진 중첩루프를 펼칠 시점에 프로세서 수와 기억공간의 현재 사용 가능한 시스템 자원 양에 제한하여 안전하면서도 가능한 최적으로 펼친다는데 있다.

• Journal of Electrical Engineering and information Science
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• 제1권2호
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• pp.15-26
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• 1996

MPAs(Massively Parallel Architectures) should address two fundamental issues for scalability: synchronization and communication latency. Dataflow architecture faces problems of excessive synchronization overhead and inefficient execution of sequential programs while they offer the ability to exploit massive parallelism inherent in programs. In contrast, MPAs based on von Neumann computational model may suffer from inefficient synchronization mechanism and communication latency. DAVRID (DAtaflow/Von Neumann RISC hybrID) is a massively parallel multithreaded architecture which takes advantages of von Neumann and dataflow models. It has good single thread performance as well as tolerates synchronization and communication latency. In this paper, we describe the DAVRID architecture in detail and evaluate its performance through simulation runs over several benchmarks.

• ETRI Journal
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• 제43권5호
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• pp.825-834
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• 2021

Based on its simplicity and user-friendly characteristics, OpenMP has become the standard model for programming on shared-memory architectures. Checkpointing-aided parallel execution (CAPE) is an approach that utilizes the discontinuous incremental checkpointing technique (DICKPT) to translate and execute OpenMP programs on distributed-memory architectures automatically. Currently, CAPE implements the OpenMP execution model by utilizing the DICKPT to distribute parallel jobs and their data to slave machines, and then collects the results after executing these distributed jobs. Although this model has been proven to be effective in terms of performance and compatibility with OpenMP on distributed-memory systems, it cannot fully exploit the capabilities of multicore processors. This paper presents a novel execution model for CAPE that utilizes two levels of parallelism. In the proposed model, we add another level of parallelism in the form of multithreaded processes on slave machines with the goal of better exploiting their multicore CPUs. Initial experimental results presented near the end of this paper demonstrate that this model provides significantly enhanced CAPE performance.