COMPSs-Mobile: parallel programming for mobile-cloud computing

The advent of Cloud and the popularization of mobile devices have led us to a shift in computing access. Computing users will have an interaction display while the real computation will be performed remotely, in the Cloud. COMPSs-Mobile is a framework that aims to ease the development of energy-efficient and high-performing applications for this environment. The framework provides an infrastructure-unaware programming model that allows developers to code regular Android applications that, transparently, are parallelized, and partially offloaded to remote resources. This paper gives an overview of the programming model and describes the internal components of the toolkit which supports it focusing on the offloading and checkpointing mechanisms. It also presents the results of some tests conducted to evaluate the behavior of the solution and to measure the potential benefits in Android applications.Peer ReviewedPostprint (published version

A hierarchic task-based programming model for distributed heterogeneous computing

Distributed computing platforms are evolving to heterogeneous ecosystems with Clusters, Grids and Clouds introducing in its computing nodes, processors with different core architectures, accelerators (i.e. GPUs, FPGAs), as well as different memories and storage devices in order to achieve better performance with lower energy consumption. As a consequence of this heterogeneity, programming applications for these distributed heterogeneous platforms becomes a complex task. Additionally to the complexity of developing an application for distributed platforms, developers must also deal now with the complexity of the different computing devices inside the node. In this article, we present a programming model that aims to facilitate the development and execution of applications in current and future distributed heterogeneous parallel architectures. This programming model is based on the hierarchical composition of the COMP Superscalar and Omp Superscalar programming models that allow developers to implement infrastructure-agnostic applications. The underlying runtime enables applications to adapt to the infrastructure without the need of maintaining different versions of the code. Our programming model proposal has been evaluated on real platforms, in terms of heterogeneous resource usage, performance and adaptation.This work has been supported by the European Commission through the Horizon 2020 Research and Innovation program under contract 687584 (TANGO project) by the Spanish Government under contract TIN2015-65316 and grant SEV-2015-0493 (Severo Ochoa Program) and by Generalitat de Catalunya under contracts 2014-SGR-1051 and 2014-SGR-1272.Peer ReviewedPostprint (author's final draft

Enabling GPU Support for the COMPSs-Mobile Framework

Using the GPUs embedded in mobile devices allows for increasing the performance of the applications running on them while reducing the energy consumption of their execution. This article presents a task-based solution for adaptative, collaborative heterogeneous computing on mobile cloud environments. To implement our proposal, we extend the COMPSs-Mobile framework – an implementation of the COMPSs programming model for building mobile applications that offload part of the computation to the Cloud – to support offloading computation to GPUs through OpenCL. To evaluate our solution, we subject the prototype to three benchmark applications representing different application patterns.This work is partially supported by the Joint-Laboratory on Extreme Scale Computing (JLESC), by the European Union through the Horizon 2020 research and innovation programme under contract 687584 (TANGO Project), by the Spanish Goverment (TIN2015-65316-P, BES-2013-067167, EEBB-2016-11272, SEV-2011-00067) and the Generalitat de Catalunya (2014-SGR-1051).Peer ReviewedPostprint (author's final draft

A mathematical formulation of the loop pipelining problem

This paper presents a mathematical model for the loop pipelining problem that considers several parameters for optimization and supports any combination of resource and timing constraints. The unrolling degree of the loop is one of the variables explored by the model. By using Farey’s series, an optimal exploration of the unrolling degree is performed and optimal solutions not considered by other methods are obtained. Finding an optimal schedule that minimizes resource and register requirements is solved by using an Integer linear programming (ILP) model. A novel paradigm called branch and prune is proposed to eficiently converge towards the optimal schedule and prune the search tree for integer solutions, thus drastically reducing the running time. This is the first formulation that combines the unrolling degree of the loop with timing and resource constraints in a mathematical model that guarantees optimal solutions.Peer ReviewedPostprint (author's final draft

Analysis of the overheads incurred due to speculation in a task based programming model

In order to efficiently utilize the ever increasing processing power of multi-cores, a programmer must extract as much parallelism as possible from a given application. However with every such attempt there is an associated overhead of its implementation. A parallelization technique is beneficial only if its respective overhead is less than the performance gains realized. In this paper we analyze the overhead of one such endeavor where, in SMPSs, speculation is used to execute tasks ahead in time. Speculation is used to overcome the synchronization pragmas in SMPSs which block the generation of work and lead to the underutilization of the available resources. TinySTM, a Software Transactional Memory library is used to maintain correctness in case of mis-speculation. In this paper, we analyze the affect of TinySTM on a set of SMPSs applications which employ speculation to improve the performance. We show that for the chosen set of benchmarks, no performance gains are achieved if the application spends more than 1% of its execution time in TinySTM.Peer ReviewedPostprint (published version

Repsol : de empresa pública a multinacional del petróleo

El Grupo Repsol se creó en 1987 como resultado final de la reordenación del sector petrolero español, configurándose como sociedad anónima de capital público que integró la práctica totalidad de las empresas públicas del sector. El artículo estudia el proceso de transformación experimentado por Repsol desde su creación, comenzando por analizar el contexto en el que se ha producido, es decir, un sector petrolero mundial sujeto a fuertes cambios a raíz de la crisis de 1973, a la que los actores públicos y privados respondieron con innovaciones de enorme calado en sus políticas y sus estrategias: de un lado, desregulación, privatización, liberalización (pero también, en sentido opuesto, nacionalizaciones), del otro, integración vertical, cambios organizativos, diversificación sectorial y geográfica, acuerdos estratégicos. El artículo analiza sucesivamente: la forma en que se pusieron en práctica esas estrategias en el caso de Repsol, los cambios estructurales que se produjeron como consecuencia en la productividad y la rentabilidad de Repsol, y la medida en que ello ha llevado a la compañía a homologarse, también al nivel de los resultados, con las grandes multinacionales del sector

Teorema de Stokes a R^n

Hom fa una revisió de la teoria d'integració de formes diferencials i en particular del seu teorema principal: el teorema de Stokes, des de les versions més clàssiques fins a les idees més modernes al voltant del tema, fent atenció a alguns resultats particularment útils i remarcables

Transparent Orchestration of Task-based Parallel Applications in Containers Platforms

This paper presents a framework to easily build and execute parallel applications in container-based distributed computing platforms in a user-transparent way. The proposed framework is a combination of the COMP Superscalar (COMPSs) programming model and runtime, which provides a straightforward way to develop task-based parallel applications from sequential codes, and containers management platforms that ease the deployment of applications in computing environments (as Docker, Mesos or Singularity). This framework provides scientists and developers with an easy way to implement parallel distributed applications and deploy them in a one-click fashion. We have built a prototype which integrates COMPSs with different containers engines in different scenarios: i) a Docker cluster, ii) a Mesos cluster, and iii) Singularity in an HPC cluster. We have evaluated the overhead in the building phase, deployment and execution of two benchmark applications compared to a Cloud testbed based on KVM and OpenStack and to the usage of bare metal nodes. We have observed an important gain in comparison to cloud environments during the building and deployment phases. This enables better adaptation of resources with respect to the computational load. In contrast, we detected an extra overhead during the execution, which is mainly due to the multi-host Docker networking.This work is partly supported by the Spanish Government through Programa Severo Ochoa (SEV-2015-0493), by the Spanish Ministry of Science and Technology through TIN2015-65316 project, by the Generalitat de Catalunya under contracts 2014-SGR-1051 and 2014-SGR-1272, and by the European Union through the Horizon 2020 research and innovation program under grant 690116 (EUBra-BIGSEA Project). Results presented in this paper were obtained using the Chameleon testbed supported by the National Science Foundation.Peer ReviewedPostprint (author's final draft

Training for museums and the National Charter for museum professions in Italy: a new prospective for development

Cadernos de SociomuseologiaTraditionally Italian universities have trained researchers and professionals in conservation: archaeologists, art historians and architects. It is only with the reform of the universities, from 1999, that the teaching of museology and museography have also been expanded.Italian museums are for the most part public museums, depending on local bodies or the national ministry; they lack autonomy and do not possess specific professional figures. The task of conservation has predominated over the other roles of museums, but with the reform of the conservation law in 2004 the definition of „museum‟ has been introduced in Italy as well, and regulations regarding the development of heritage have been issued; in addition the Regions have also taken on a more active role for museums belonging to local bodies and for the development of their territory.Museum professions are not officially recognised, but the museum community, through the various associations and ICOM Italia, has put together a document to act as a general reference, the National Charter of Museum Professions, which has been followed by the Manual of Museum Professions in Europe. Now there is a need to plan the content and outlines ofvocational training courses for museum professionals, together withthe universities, the regions and the museums themselves, alongwith the associations and ICOM – ICTOP, utilising the mostinnovative Master‟s courses which offer an interdisciplinaryapproach, a methodology which combines theory and practice, andan element of hands-on experimentation in museums, or withmuseums