Página 1 dos resultados de 103 itens digitais encontrados em 0.004 segundos

Evaluating applications performance in a multi-networked cluster

Alves, Albano; Pina, António; Rufino, José; Exposto, José
Fonte: ACTA Press Publicador: ACTA Press
Tipo: Conferência ou Objeto de Conferência
ENG
Relevância na Pesquisa
56.48%
Traditionally, a cluster is defined as a collection of homogeneous nodes interconnected by a single high performance communication technology. However, in some cases, cluster nodes may be organized into several partitions – subclusters – internally interconnected by one or more selected SAN technologies. In order to constitute a multi-networked cluster, sub-clusters must share a common SAN technology or a bridge facility must be used. In this paper we show how RoCL – a lightweight user-level communication library designed to support multi-threading in a multi-networked environment – manages to exploit such cluster organization. Performance evaluation results obtained by using two partitions of Myrinet and Gigabit SMP nodes demonstrate the usefulness of our approach both for low-level and high-level operation.

RoCL: a resource oriented communication library

Alves, Albano; Pina, António; Rufino, José; Exposto, José
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
ENG; ENG
Relevância na Pesquisa
46.34%
RoCL is a communication library that aims to exploit the low-level communication facilities of today’s cluster networking hardware and to merge, via the resource oriented paradigm, those facilities and the high-level degree of parallelism achieved on SMP systems through multi-threading. The communication model defines three major entities – contexts, resources and buffers – which permit the design of high-level solutions. A low-level distributed directory is used to support resource registering and discovering. The usefulness and applicability of RoCL is briefly addressed through a basic modelling example – the implementation of TPVM over RoCL. Performance results for Myrinet and Gigabit Ethernet, currently supported in RoCL through GM and MVIA, respectively, are also presented.

R-SAP: a multi-threading computational pipeline for the characterization of high-throughput RNA-sequencing data

Mittal, Vinay K.; McDonald, John F.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.53%
The rapid expansion in the quantity and quality of RNA-Seq data requires the development of sophisticated high-performance bioinformatics tools capable of rapidly transforming this data into meaningful information that is easily interpretable by biologists. Currently available analysis tools are often not easily installed by the general biologist and most of them lack inherent parallel processing capabilities widely recognized as an essential feature of next-generation bioinformatics tools. We present here a user-friendly and fully automated RNA-Seq analysis pipeline (R-SAP) with built-in multi-threading capability to analyze and quantitate high-throughput RNA-Seq datasets. R-SAP follows a hierarchical decision making procedure to accurately characterize various classes of transcripts and achieves a near linear decrease in data processing time as a result of increased multi-threading. In addition, RNA expression level estimates obtained using R-SAP display high concordance with levels measured by microarrays.

Multi-Threading and Shared-Memory Pool Techniques for Authorization of Credit Card Systems Using Java

Hamid, Siti Hafizah AB.; University of Malaya; Nasir, Mohd Hairul Nizam M.; University of Malaya; Ming, Wong Yew; University of Malaya; Hassan, Hazrina; University of Malaya
Fonte: Editora da UFLA Publicador: Editora da UFLA
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Peer-reviewed Article Formato: application/pdf
Publicado em 26/08/2015 ENG
Relevância na Pesquisa
46.34%

An efficient threading model to boost server performance

Chanda, Anupam
Fonte: Universidade Rice Publicador: Universidade Rice
ENG
Relevância na Pesquisa
36.6%
Multi-threading is a popular choice for server architecture. Widely used servers, like the Apache web server and the MySQL database server, are written in a multi-threaded fashion. We investigate the effects of thread architecture on server performance from two angles: (1) number of user threads per kernel thread, and (2) use of blocking I/O vs. non-blocking I/O. We propose N-to-M threads with non-blocking I/O, a novel threading model, to provide higher performance for servers, and explain its advantages over other existing thread architectures, viz., 1-to-1 threads with blocking I/O, N-to-1 threads with non-blocking I/O, and N-to-M threads with blocking I/O. We demonstrate the efficacy of this threading model by showing performance improvement for Apache and MySQL. Results show that our threading model provides a performance improvement of 10--22% for Apache (for synthetic and real workloads), and 10--17% for MySQL (for TPC-W workload) over existing thread models.

Analysis and improvement of performance and power consumption of chip multi-threading SMP architectures

Grant, Ryan Eric
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado Formato: 871480 bytes; application/pdf
EN; EN
Relevância na Pesquisa
36.19%
Emerging processor technologies are becoming commercially available that make multi-processor capabilities affordable for use in a large number of computer systems. Increasing power consumption by this next generation of processors is a growing concern as the cost of operating such systems continues to increase. It is important to understand the characteristics of these emerging technologies in order to enhance their performance. By understanding the characteristics of high performance computing workloads on real systems, the overall efficiency with which such workloads are executed can be increased. In addition, it is important to determine the best trade-off between system performance and power consumption using the variety of system configurations that are possible with these new technologies. This thesis seeks to provide a comprehensive presentation of the performance characteristics of several real commercially available simultaneous-multithreading multi-processor architectures and provide recommendations to improve overall system performance. As well, it will provide solutions to reduce the power consumption of such systems while minimizing the performance impact of these techniques on the system. The results of the research conducted show that the new scheduler proposed in this thesis is capable of providing significant increases in efficiency for traditional and emerging multi-processor technologies. These findings are confirmed using real system performance and power measurements.; Thesis (Master...

Extended perspective system visualizer

Burgess, Robin Charles Rosa
Fonte: Universidade de Lisboa Publicador: Universidade de Lisboa
Tipo: Dissertação de Mestrado
Publicado em //2014 ENG
Relevância na Pesquisa
46.53%
Tese de mestrado, Engenharia Informática (Interacção e Conhecimento), Universidade de Lisboa, Faculdade de Ciências, 2014; A projecção perspectiva linear tem sido o modo predominante de desenhar imagens de espaços tridimensionais há séculos, sejam estes desenhos manuais ou computacionais. Em particular, os arquitectos usam o sistema perspéctico linear no desenho formal como forma de representar o seu trabalho como este seria observado através da visão humana. Porém, este sistema perspéctico é limitado nesta capacidade. Quando se utilizam ângulos de visão mais alargados, os desenhos que utilizam projecção perspectiva linear manifestam uma distorção que dificulta a interpretação da imagem e limitam a capacidade desta perspectiva de verdadeiramente representar a visão humana. Aos 180º de ângulo de visão, o máximo possível neste sistema, a imagem passa a ser inteiramente irreconhecível. Formas de projecção perspectiva não lineares, ou curvilíneas, como a perspectiva cilíndrica ou panorâmica ou a perspectiva esférica, não apresentam a mesma limitação. Usando estas perspectivas, o ângulo de visão pode ser alargado até aos 360º sem que esta distorção apareça. Porém, estes sistemas também não são soluções perfeitas já que a rectilinearidade não é preservada. O Sistema Perspéctico Expandido (EPS) foi criado por membros da equipa NAADIR (New Approach on Architectural Drawings Integrating computeR descriptions) para responder às limitações dos sistemas individuais existentes. O seu trabalho...

Thread algebra for poly-threading

Bergstra, J. A.; Middelburg, C. A.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.34%
Threads as considered in basic thread algebra are primarily looked upon as behaviours exhibited by sequential programs on execution. It is a fact of life that sequential programs are often fragmented. Consequently, fragmented program behaviours are frequently found. In this paper, we consider this phenomenon. We extend basic thread algebra with the barest mechanism for sequencing of threads that are taken for fragments. This mechanism, called poly-threading, supports both autonomous and non-autonomous thread selection in sequencing. We relate the resulting theory to the algebraic theory of processes known as ACP and use it to describe analytic execution architectures suited for fragmented programs. We also consider the case where the steps of fragmented program behaviours are interleaved in the ways of non-distributed and distributed multi-threading.; Comment: 24 pages, sections 9, 10, and 11 are added

High-Level Multi-Threading in hProlog

Van Overveldt, Timon; Demoen, Bart
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.53%
A new high-level interface to multi-threading in Prolog, implemented in hProlog, is described. Modern CPUs often contain multiple cores and through high-level multi-threading a programmer can leverage this power without having to worry about low-level details. Two common types of high-level explicit parallelism are discussed: independent and-parallelism and competitive or-parallelism. A new type of explicit parallelism, pipeline parallelism, is proposed. This new type can be used in certain cases where independent and-parallelism and competitive or-parallelism cannot be used.; Comment: Online Proceedings of the 11th International Colloquium on Implementation of Constraint LOgic Programming Systems (CICLOPS 2011), Lexington, KY, U.S.A., July 10, 2011

Prophet: A Speculative Multi-threading Execution Model with Architectural Support Based on CMP

Zhaoyu, Dong; Bing, Gao; Yinliang, Zhao; Shaolong, Song; Yanning, Du
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 10/12/2014
Relevância na Pesquisa
46.57%
Speculative multi-threading (SpMT) has been proposed as a perspective method to exploit Chip Multiprocessors (CMP) hardware potential. It is a thread level speculation (TLS) model mainly depending on software and hardware co-design. This paper researches speculative thread-level parallelism of general purpose programs and a speculative multi-threading execution model called Prophet is presented. The architectural support for Prophet execution model is designed based on CMP. In Prophet the inter-thread data dependency are predicted by pre-computation slice (p-slice) to reduce RAW violation. Prophet multi-versioning Cache system along with thread state control mechanism in architectural support are utilized for buffering the speculative data, and a snooping bus based cache coherence protocol is used to detect data dependence violation. The simulation-based evaluation shows that the Prophet system could achieve significant speedup for general-purpose programs.; Comment: 9 pages

Personal Multi-threading

Bergstra, Jan A.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 11/12/2014
Relevância na Pesquisa
46.53%
Multi-threading allows agents to pursue a heterogeneous collection of tasks in an orderly manner. The view of multi-threading that emerges from thread algebra is applied to the case where a single agent, who may be human, maintains a hierarchical multithread as an architecture of its own activities.

Multi-threaded ASP Solving with clasp

Gebser, Martin; Kaufmann, Benjamin; Schaub, Torsten
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 11/10/2012
Relevância na Pesquisa
36.15%
We present the new multi-threaded version of the state-of-the-art answer set solver clasp. We detail its component and communication architecture and illustrate how they support the principal functionalities of clasp. Also, we provide some insights into the data representation used for different constraint types handled by clasp. All this is accompanied by an extensive experimental analysis of the major features related to multi-threading in clasp.; Comment: 19 pages, 5 figures, to appear in Theory and Practice of Logic Programming

Towards Multi-Threaded Local Tabling Using a Common Table Space

Areias, Miguel; Rocha, Ricardo
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.57%
Multi-threading is currently supported by several well-known Prolog systems providing a highly portable solution for applications that can benefit from concurrency. When multi-threading is combined with tabling, we can exploit the power of higher procedural control and declarative semantics. However, despite the availability of both threads and tabling in some Prolog systems, the implementation of these two features implies complex ties to each other and to the underlying engine. Until now, XSB was the only Prolog system combining multi-threading with tabling. In XSB, tables may be either private or shared between threads. While thread-private tables are easier to implement, shared tables have all the associated issues of locking, synchronization and potential deadlocks. In this paper, we propose an alternative view to XSB's approach. In our proposal, each thread views its tables as private but, at the engine level, we use a common table space where tables are shared among all threads. We present three designs for our common table space approach: No-Sharing (NS) (similar to XSB's private tables), Subgoal-Sharing (SS) and Full-Sharing (FS). The primary goal of this work was to reduce the memory usage for the table space but, our experimental results...

Multi-Threading And Message Communication In Qu-Prolog

Clark, Keith L.; Robinson, Peter J.; Hagen, Richard
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 24/04/2004
Relevância na Pesquisa
46.4%
This paper presents the multi-threading and internet message communication capabilities of Qu-Prolog. Message addresses are symbolic and the communications package provides high-level support that completely hides details of IP addresses and port numbers as well as the underlying TCP/IP transport layer. The combination of the multi-threads and the high level inter-thread message communications provide simple, powerful support for implementing internet distributed intelligent applications.; Comment: Appeared in Theory and Practice of Logic Programming, vol. 1, no. 3, 2001

High-Performance Physics Simulations Using Multi-Core CPUs and GPGPUs in a Volunteer Computing Context

Karimi, Kamran; Dickson, Neil G.; Hamze, Firas
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 31/03/2010
Relevância na Pesquisa
36.4%
This paper presents two conceptually simple methods for parallelizing a Parallel Tempering Monte Carlo simulation in a distributed volunteer computing context, where computers belonging to the general public are used. The first method uses conventional multi-threading. The second method uses CUDA, a graphics card computing system. Parallel Tempering is described, and challenges such as parallel random number generation and mapping of Monte Carlo chains to different threads are explained. While conventional multi-threading on CPUs is well-established, GPGPU programming techniques and technologies are still developing and present several challenges, such as the effective use of a relatively large number of threads. Having multiple chains in Parallel Tempering allows parallelization in a manner that is similar to the serial algorithm. Volunteer computing introduces important constraints to high performance computing, and we show that both versions of the application are able to adapt themselves to the varying and unpredictable computing resources of volunteers' computers, while leaving the machines responsive enough to use. We present experiments to show the scalable performance of these two approaches, and indicate that the efficiency of the methods increases with bigger problem sizes.; Comment: 15 pages...

A Simple Method to Produce Algorithmic MIDI Music based on Randomness, Simple Probabilities and Multi-Threading

Tzitzikas, Yannis
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 14/12/2013
Relevância na Pesquisa
46.34%
This paper introduces a simple method for producing multichannel MIDI music that is based on randomness and simple probabilities. One distinctive feature of the method is that it produces and sends in parallel to the sound card more than one unsynchronized channels by exploiting the multi-threading capabilities of general purpose programming languages. As consequence the derived sound offers a quite ``full" and ``unpredictable" acoustic experience to the listener. Subsequently the paper reports the results of an evaluation with users. The results were very surprising: the majority of users responded that they could tolerate this music in various occasions.; Comment: 7 pages, 5 figures

OCCA: A unified approach to multi-threading languages

Medina, David S; St-Cyr, Amik; Warburton, T.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 04/03/2014
Relevância na Pesquisa
36.22%
The inability to predict lasting languages and architectures led us to develop OCCA, a C++ library focused on host-device interaction. Using run-time compilation and macro expansions, the result is a novel single kernel language that expands to multiple threading languages. Currently, OCCA supports device kernel expansions for the OpenMP, OpenCL, and CUDA platforms. Computational results using finite difference, spectral element and discontinuous Galerkin methods show OCCA delivers portable high performance in different architectures and platforms.; Comment: 25 pages, 6 figures, 9 code listings, 8 tables, Submitted to the SIAM Journal on Scientific Computing (SISC), presented at the Oil & Gas Workshop 2014 at Rice University

A simple and efficient explicit parallelization of logic programs using low-level threading primitives

Saha, Diptikalyan; Fodor, Paul
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.34%
In this work, we present an automatic way to parallelize logic programs for finding all the answers to queries using a transformation to low level threading primitives. Although much work has been done in parallelization of logic programming more than a decade ago (e.g., Aurora, Muse, YapOR), the current state of parallelizing logic programs is still very poor. This work presents a way for parallelism of tabled logic programs in XSB Prolog under the well founded semantics. An important contribution of this work relies in merging answer-tables from multiple children threads without incurring copying or full-sharing and synchronization of data-structures. The implementation of the parent-children shared answer-tables surpasses in efficiency all the other data-structures currently implemented for completion of answers in parallelization using multi-threading. The transformation and its lower-level answer merging predicates were implemented as an extension to the XSB system.

Análisis de prestaciones de procesadores multi-core y multi-thread

Boba Yunta, Javier; Moure López, Juan Carlos
Fonte: Universidade Autônoma de Barcelona Publicador: Universidade Autônoma de Barcelona
Tipo: Trabalho de Conclusão de Curso Formato: application/pdf
Publicado em //2009 SPA
Relevância na Pesquisa
36.98%
Los procesadores multi-core y el multi-threading por hardware permiten aumentar el rendimiento de las aplicaciones. Por un lado, los procesadores multi-core combinan 2 o más procesadores en un mismo chip. Por otro lado, el multi-threading por hardware es una técnica que incrementa la utilización de los recursos del procesador. Este trabajo presenta un análisis de rendimiento de los resultados obtenidos en dos aplicaciones, multiplicación de matrices densas y transformada rápida de Fourier. Ambas aplicaciones se han ejecutado en arquitecturas multi-core que explotan el paralelismo a nivel de thread pero con un modelo de multi-threading diferente. Los resultados obtenidos muestran la importancia de entender y saber analizar el efecto del multi-core y multi-threading en el rendimiento.; Els processadors multi-core y el multi-threading per hardware permeten augmentar el rendiment de les aplicacions. Per un costat, els processadors multi-core combinen 2 o més processadors en un mateix xip. Per l'altre costat, el multi-threading per hardware és una tècnica que incrementa la utilització dels recursos del processador. Aquest treball presenta una anàlisi de rendiment dels resultats obtinguts en dues aplicacions, la multiplicació de matrius denses i la transformada ràpida de Fourier. Les dues aplicacions s'han executat en arquitectures multi-core que exploten el paral·lelisme a nivell de thread però amb un model diferent de multi-threading. Els resultats obtinguts mostren la importància d'entendre i saber analitzar l'efecte de multi-core i multi-threading en el rendiment.; Multi-core processors and hardware multi-threading increases the application performance. On one hand...

Distributed multi-threading in GNU prolog

Morgadinho, Nuno Eduardo Quaresma
Fonte: Universidade de Évora Publicador: Universidade de Évora
Tipo: Dissertação de Mestrado
ENG
Relevância na Pesquisa
66.53%
Embora a computação paralela já tenha sido alvo de inúmeros estudos, o processo de a tornar acessível as massas ainda mal começou. Através da combinação com o Prolog de um ambiente de programação distribuída e multithreaded, como o PM2, torna-se possível ter computações paralelas e concorrentes usando programação em logica. Com este objetivo foi desenvolvido o PM2-Prolog, um interface Prolog para o sistema PM2. Tal sistema permite correr aplicações Prolog multithreaded em múltiplas instâncias do GNU Prolog num ambiente distribuído, tirando, assim, partido dos recursos disponíveis nos computadores ligados numa rede. Em problemas computacionalmente pesados, onde o tempo de execução é crucial, existe particular vantagem em usar este sistema. A API do sistema oferece primitivas para gestão de threads e para comunicação explícita entre threads. Testes preliminares mostram um ganho de desempenho quase linear, em comparação com uma versão sequencial. /ABSTRACT - Although parallel computing has been widely researched, the process of bringing concurrency and parallel programming to the mainstream has just begun. Combining a distributed multi-threading environment like PM2 with Prolog, opens the way to exploit concurrency and parallel computing using logic programming. To achieve such a purpose...