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A Tool for Selecting the Right Target Machine for Parallel Scientific Applications

Procedia computer Science 2013年 18卷 1824-1833页

作者： Javier Panadero Alvaro Wong Dolores Rexachs Emilio Luque Computer Architecture and Operating System Department Universitat Autonoma de Barcelona Barcelona SPAIN

Analyzing and predicting performance in parallel applications is a great challenge for scientific programmers due to its com- plexity. Analyzing parallel application behavior is not a trivial process and it requires spending a large amount of time and effort to understand the behavior of the application algorithms during execution. We have developed PAS2P toolkit from PAS2P methodology. This methodology strives to characterize the behavior of MPI applications to identify and extract repre- sentative phases and create a signature, which will be used to analyze the application behavior and predict its execution time in different target systems. Applying this methodology is a non-trivial process for users, for this reason we have developed the proposal toolkit, which allows users to make the whole process, from creating a signature to executing it on target systems, in user-space in an easy and fully automatic way. PAS2P toolkit has been validated, making clear the advantages of the signature, with its execution time being much lower than the whole application execution time (around 7% of the total execution time), with a high quality prediction of around 96%.

关键词： Performance toolkit Performance Prediction Parallel Application Signature

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An Optimization for MapReduce Frameworks in Multi-core architectures

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Procedia computer Science 2013年 18卷 2587-2590页

作者： Tharso Ferreira Antonio Espinosa Juan Carlos Moure Porfidio Hernández Computer Architecture and Operating System Department Universitat Auto‘noma of Barcelona 08193 Bellaterra Barcelona Spain

MapReduce simplifies parallel programming, abstracting the programmer responsibilities as synchronization and task man- agement. The paradigm allows the programmer to write sequential code which is automatically parallelized. The MapReduce frameworks developed today are designed for situations where all keys generated by the Map phase must fit into main memory. However certain types of workload have a distribution of keys that provoke a growth of intermediate data structures, exceeding the amount of available main memory. Based on the behavior of MapReduce frameworks in multi-core architectures for these types of workload, we promote an extension of the original strategy of MapReduce for multi-core architectures. We present an extension in memory hierarchy, hard disk and main memory, which has as objective to reduce the use of main memory, as well as reducing the page faults, caused by the use of swap. The main goal of our extension is to ensure an acceptable performance of MapReduce, when intermediate data structures do not fit in main memory and it is necessary to make use of a secondary memory.

关键词： MapReduce Multicore Processors Threads Main Memory Virtual Memory

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Enhanced Method for the Signature Adaptability to the Application Behavior

Enhanced Method for the Signature Adaptability to the Applic...

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IEEE International Conference on Trust, Security and Privacy in Computing and Communications (TrustCom)

作者： Alvaro Wong Dolores Rexachs Emilio Luque Computer Architecture and Operating System Department Universidad Autonoma de Barcelona Barcelona SPAIN

ISBN: (纸本)9781479914449

Predicting performance of parallel applications using benchmarks is becoming more complex. Each parallel application has different behavior and it is difficult to know which is the benchmark that most closely resembles the application, therefore the benchmarks have a low representativeness of real programs. We are proposing the users to predict the performance of their applications by generating a signature using a method called Parallel Application Signature for Performance Prediction (PAS2P), which represents the core of their applications. We are presenting an enhanced method for the signature adaptability to the application behavior. Until now, phases were considered independently, each one had a checkpoint, but now we analyze whether they are contiguous and can form a group. This is done by decreasing the storage needed for the signature, slightly increasing the signature execution time in order to predict the performance of the applications thus compensating the execution time of the signature and its size (MB). We show results from building different signatures for the same applications to allow the user to select between different options in order to create the signature.

关键词： Phase measurement Benchmark testing Instruments Analytical models Time measurement Visualization Libraries

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The EGI software vulnerability group and EMI 2

The EGI software vulnerability group and EMI

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2012 EGI Community Forum / EMI 2nd Technical Conference, EGICF-EMITC 2012

作者： Cornwall, L.A. Heymann, E. STFC Rutherford Appleton Laboratory Harwell Oxford DidcotOX11 OQX United Kingdom Universitat Autonoma de Barcelona Computer Architecture and Operating System Department Campus de Bellaterra Bellaterra Barcelona08193 Spain

This provides an overview of the activities of the European Grid Infrastructure (EGI) Software Vulnerability Group (SVG) and progress made in addressing vulnerabilities in collaboration with the European Middleware Initiative (EMI). This includes a summary of the formally agreed process for handling Software Vulnerabilities reported to the EGI SVG. It also describes the pro-active searching for vulnerabilities via ‘Vulnerability Assessment’ of software packages. Steps taken to prevent new vulnerabilities entering the infrastructure are described. The emphasis is on Grid Middleware as vulnerabilities in this software are generally not handled elsewhere. The collaboration with the Grid middleware software providers, in particular EMI, is described. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence.

关键词： Middleware

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Predicting parallel applications performance using signatures: The workload effect

Predicting parallel applications performance using signature...

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9th ACS/IEEE International Conference on computer systems and Applications, AICCSA 2011

作者： Canillas, J. Martinez Wong, A. Rexachs, D. Luque, E. Department of Computer Architecture and Operating System Universitat Autònoma de Barcelona Barcelona Spain

ISBN: (纸本)9781457704741

Being able to accurately estimate how an application will perform in a specific computational system provides many useful benefits and can result in smarter decisions. In this work we present a novel approach to model the behavior of message passing parallel applications. Based in the concept of signatures, which are the most relevant parts of an application (phases), we are able to build a model that allows us to predict the application execution time in different systems with variable input data size. Executing these signatures with different input data sizes defines a program's behavior partial function. Using regression we can generalize this behavior function to predict an application performance in a target system with other input data size within a predefined range. We explain our methodology and in order to validate the proposal present results using a synthetic program and well known applications. © 2011 IEEE.

关键词： Message passing

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Including the workload effect in the parallel program signature

Including the workload effect in the parallel program signat...

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13th IEEE International Workshop on FTDCS 2011, the 8th International Conference on ATC 2011, the 8th International Conference on UIC 2011 and the 13th IEEE International Conference on HPCC 2011

作者： Canillas, J. Martinez Wong, A. Rexachs, D. Luque, E. Department of Computer Architecture and Operating System Universitat Autònoma de Barcelona Barcelona Spain

ISBN: (纸本)9780769545387

Performance prediction and application behavior modeling have been the subject of extensive research that aims to estimate applications performance with acceptable precision. In this paper we present a novel approach to model the behavior of message passing parallel applications. There are many dimensions to consider while predicting a deterministic application behavior. Two dimensions that affect an application performance are the computational resources available and the size of its input data used in the computation. Based on the concept of signatures, we are able to build a model that allows us to predict applications execution time in different systems with variable input data size within a predefined range. Our approach generates signatures, which consist of the most relevant parts of an application (phases). Executing these phases for different workloads partially defines a program's behavior function. By using regression analysis we are able to generalize this behavior function to predict an application performance in a target system with any input data size within a predefined range. We explain our methodology and in order to validate the proposal, we present results using a synthetic program and well-known applications. We were able to estimate the total execution time for a input data size range with an average error of 4% executing, at most, three signatures that represent less than the 10% of the total application execution time. © 2011 IEEE.

关键词： Regression analysis

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Improving Probe Usability

Improving Probe Usability

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International Conference on Advanced Information Networking and Applications Workshops (AINAW)

作者： Alexandre Strube Dolores Rexachs Emilio Luque Universitat Autònoma de Barcelona Computer Architecture and Operating System Department (CAOS) Barcelona SPAIN

During our research for characterizing individual computing nodes using Software Probes, one of the remaining issues for quickly probing them was that of the checkpoints' sizes. This article shows the different approaches we used in order to reduce the Probes' sizes. We demonstrate that in some cases it is possible to reduce the set of Probes of an application up to 95% of its original size, thus making our approach for machine characterization useful even through slow networks such as the Internet.

关键词： Probes Benchmark testing Phase measurement Time measurement Kernel Internet

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Active learning processes to study memory hierarchy on multicore systems

Active learning processes to study memory hierarchy on multi...

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作者： Corredor, John Moure, Juan Carlos Rexachs, Dolores Franco, Daniel Luque, Emilio Universitat Autonoma de Barcelona Computer Architecture and Operating System Department Barcelona Spain

A current challenge for computer users is to fully exploit performance of new Multicore systems. We propose a methodology for students in computational science to analyze the effect of memory hierarchy on application performance. The analysis is proposed in a experimental environment consisting of different systems with different configurations of the memory hierarchy. The new Multicore systems put tremendous pressure on memory hierarchy systems. The pressure is because, unfortunately, the effectiveness of the computing power offered by Multicore, is affected by the data communications inter-chip and off-chip to the memory hierarchy, leading to significant problems in performance for many parallel applications. In the scope of computer science, it is important that students understand these problems. This methodology was successfully applied to students, where they acquired a significant improvement in their parallel application metrics assessment as was demonstrated in our evaluation.

关键词： Students

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A tool for efficient execution of SPMD applications on multicore clusters

A tool for efficient execution of SPMD applications on multi...

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作者： Muresano, Ronal Rexachs, Dolores Luque, Emilio Universitat Autonoma de Barcelona Computer Architecture and Operating System Department C.P 08293 Barcelona Spain

A challenge for parallel programmers is to efficiently execute traditional MPI applications, designed to be run in a cluster of single core nodes, on a multicore cluster. Multicore clusters include communication heterogeneities which have to be handled carefully to improve efficiency and speedup. This research presents an execution tool developed for SPMD applications which is focused on managing communications heterogeneities, distributing the workload among cores and enhancing parallel performance on multicore clusters. Our tool has been designed through using an execution methodology which includes mapping and scheduling strategies. The tool integrates five modules which give programmers a method to execute their applications efficiently. This tool is centered on improving SPMD applications designed to use MPI for communications. These applications were selected because they are the most commonly used in parallel computing. Also, these applications are chosen due to their data synchronization and communications volumes which can generate communication imbalance issues. The novel contribution of this tool is to permit programmers to find a minimum execution time, while the efficiency level is maintained over a defined threshold. Our tool has been tested in different multicore clusters and with a set of scientific applications. The results obtained show a considerable improvement in the applications efficiency when the tool is applied.

关键词： Efficiency

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Active learning processes to study memory hierarchy on Multicore systems

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Procedia computer Science 2010年第1期1卷 921-930页

作者： John Corredor Juan Carlos Moure Dolores Rexachs Daniel Franco Emilio Luque Universitat Autònoma de Barcelona o Computer Architecture and Operating System Department Barcelona SPAIN

A current challenge for computer users is to fully exploit performance of new Multicore systems. We propose a methodology for students in computational science to analyze the effect of memory hierarchy on application performance. The analysis is proposed in a experimental environment consisting of different systems with different configurations of memory hierarchy. New Multicore systems put tremendous pressure on memory hierarchy systems. The pressure is because, unfortunately, the effectiveness of the computing power offered by Multicore is affected by the data communications inter-chip and off-chip to the memory hierarchy, leading to significant problems in performance for many parallel applications. In the scope of computer science, it is important that students understand these problems. This methodology was successfully applied to students, where they acquired a significant improvement in their parallel application metrics assessment as was demonstrated in our evaluation.

关键词： Active learning Hierarchy memory Performance counters

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