10,001 research outputs found
A Taxonomy of Workflow Management Systems for Grid Computing
With the advent of Grid and application technologies, scientists and
engineers are building more and more complex applications to manage and process
large data sets, and execute scientific experiments on distributed resources.
Such application scenarios require means for composing and executing complex
workflows. Therefore, many efforts have been made towards the development of
workflow management systems for Grid computing. In this paper, we propose a
taxonomy that characterizes and classifies various approaches for building and
executing workflows on Grids. We also survey several representative Grid
workflow systems developed by various projects world-wide to demonstrate the
comprehensiveness of the taxonomy. The taxonomy not only highlights the design
and engineering similarities and differences of state-of-the-art in Grid
workflow systems, but also identifies the areas that need further research.Comment: 29 pages, 15 figure
DALiuGE: A Graph Execution Framework for Harnessing the Astronomical Data Deluge
The Data Activated Liu Graph Engine - DALiuGE - is an execution framework for
processing large astronomical datasets at a scale required by the Square
Kilometre Array Phase 1 (SKA1). It includes an interface for expressing complex
data reduction pipelines consisting of both data sets and algorithmic
components and an implementation run-time to execute such pipelines on
distributed resources. By mapping the logical view of a pipeline to its
physical realisation, DALiuGE separates the concerns of multiple stakeholders,
allowing them to collectively optimise large-scale data processing solutions in
a coherent manner. The execution in DALiuGE is data-activated, where each
individual data item autonomously triggers the processing on itself. Such
decentralisation also makes the execution framework very scalable and flexible,
supporting pipeline sizes ranging from less than ten tasks running on a laptop
to tens of millions of concurrent tasks on the second fastest supercomputer in
the world. DALiuGE has been used in production for reducing interferometry data
sets from the Karl E. Jansky Very Large Array and the Mingantu Ultrawide
Spectral Radioheliograph; and is being developed as the execution framework
prototype for the Science Data Processor (SDP) consortium of the Square
Kilometre Array (SKA) telescope. This paper presents a technical overview of
DALiuGE and discusses case studies from the CHILES and MUSER projects that use
DALiuGE to execute production pipelines. In a companion paper, we provide
in-depth analysis of DALiuGE's scalability to very large numbers of tasks on
two supercomputing facilities.Comment: 31 pages, 12 figures, currently under review by Astronomy and
Computin
Modeling Scalability of Distributed Machine Learning
Present day machine learning is computationally intensive and processes large
amounts of data. It is implemented in a distributed fashion in order to address
these scalability issues. The work is parallelized across a number of computing
nodes. It is usually hard to estimate in advance how many nodes to use for a
particular workload. We propose a simple framework for estimating the
scalability of distributed machine learning algorithms. We measure the
scalability by means of the speedup an algorithm achieves with more nodes. We
propose time complexity models for gradient descent and graphical model
inference. We validate our models with experiments on deep learning training
and belief propagation. This framework was used to study the scalability of
machine learning algorithms in Apache Spark.Comment: 6 pages, 4 figures, appears at ICDE 201
The Family of MapReduce and Large Scale Data Processing Systems
In the last two decades, the continuous increase of computational power has
produced an overwhelming flow of data which has called for a paradigm shift in
the computing architecture and large scale data processing mechanisms.
MapReduce is a simple and powerful programming model that enables easy
development of scalable parallel applications to process vast amounts of data
on large clusters of commodity machines. It isolates the application from the
details of running a distributed program such as issues on data distribution,
scheduling and fault tolerance. However, the original implementation of the
MapReduce framework had some limitations that have been tackled by many
research efforts in several followup works after its introduction. This article
provides a comprehensive survey for a family of approaches and mechanisms of
large scale data processing mechanisms that have been implemented based on the
original idea of the MapReduce framework and are currently gaining a lot of
momentum in both research and industrial communities. We also cover a set of
introduced systems that have been implemented to provide declarative
programming interfaces on top of the MapReduce framework. In addition, we
review several large scale data processing systems that resemble some of the
ideas of the MapReduce framework for different purposes and application
scenarios. Finally, we discuss some of the future research directions for
implementing the next generation of MapReduce-like solutions.Comment: arXiv admin note: text overlap with arXiv:1105.4252 by other author
Multi-criteria scheduling of pipeline workflows
Mapping workflow applications onto parallel platforms is a challenging
problem, even for simple application patterns such as pipeline graphs. Several
antagonist criteria should be optimized, such as throughput and latency (or a
combination). In this paper, we study the complexity of the bi-criteria mapping
problem for pipeline graphs on communication homogeneous platforms. In
particular, we assess the complexity of the well-known chains-to-chains problem
for different-speed processors, which turns out to be NP-hard. We provide
several efficient polynomial bi-criteria heuristics, and their relative
performance is evaluated through extensive simulations
A Survey of Pipelined Workflow Scheduling: Models and Algorithms
International audienceA large class of applications need to execute the same workflow on different data sets of identical size. Efficient execution of such applications necessitates intelligent distribution of the application components and tasks on a parallel machine, and the execution can be orchestrated by utilizing task-, data-, pipelined-, and/or replicated-parallelism. The scheduling problem that encompasses all of these techniques is called pipelined workflow scheduling, and it has been widely studied in the last decade. Multiple models and algorithms have flourished to tackle various programming paradigms, constraints, machine behaviors or optimization goals. This paper surveys the field by summing up and structuring known results and approaches
Developing Real-Time Emergency Management Applications: Methodology for a Novel Programming Model Approach
The last years have been characterized by the arising of highly distributed computing
platforms composed of a heterogeneity of computing and communication resources including
centralized high-performance computing architectures (e.g. clusters or large shared-memory
machines), as well as multi-/many-core components also integrated into mobile nodes
and network facilities. The emerging of computational paradigms such as Grid and Cloud
Computing, provides potential solutions to integrate such platforms with data systems, natural
phenomena simulations, knowledge discovery and decision support systems responding to a
dynamic demand of remote computing and communication resources and services.
In this context time-critical applications, notably emergency management systems, are
composed of complex sets of application components specialized for executing specific
computations, which are able to cooperate in such a way as to perform a global goal in a
distributed manner. Since the last years the scientific community has been involved in facing
with the programming issues of distributed systems, aimed at the definition of applications
featuring an increasing complexity in the number of distributed components, in the spatial
distribution and cooperation between interested parties and in their degree of heterogeneity.
Over the last decade the research trend in distributed computing has been focused on
a crucial objective. The wide-ranging composition of distributed platforms in terms of
different classes of computing nodes and network technologies, the strong diffusion of
applications that require real-time elaborations and online compute-intensive processing as
in the case of emergency management systems, lead to a pronounced tendency of systems
towards properties like self-managing, self-organization, self-controlling and strictly speaking
adaptivity.
Adaptivity implies the development, deployment, execution and management of applications
that, in general, are dynamic in nature. Dynamicity concerns the number and the specific
identification of cooperating components, the deployment and composition of the most
suitable versions of software components on processing and networking resources and
services, i.e., both the quantity and the quality of the application components to achieve
the needed Quality of Service (QoS). In time-critical applications the QoS specification
can dynamically vary during the execution, according to the user intentions and the
Developing Real-Time Emergency
Management Applications: Methodology for
a Novel Programming Model Approach
Gabriele Mencagli and Marco Vanneschi
Department of Computer Science, University of Pisa, L. Bruno Pontecorvo, Pisa
Italy
2
2 Will-be-set-by-IN-TECH
information produced by sensors and services, as well as according to the monitored state
and performance of networks and nodes.
The general reference point for this kind of systems is the Grid paradigm which, by
definition, aims to enable the access, selection and aggregation of a variety of distributed and
heterogeneous resources and services. However, though notable advancements have been
achieved in recent years, current Grid technology is not yet able to supply the needed software
tools with the features of high adaptivity, ubiquity, proactivity, self-organization, scalability
and performance, interoperability, as well as fault tolerance and security, of the emerging
applications.
For this reason in this chapter we will study a methodology for designing high-performance
computations able to exploit the heterogeneity and dynamicity of distributed environments
by expressing adaptivity and QoS-awareness directly at the application level. An effective
approach needs to address issues like QoS predictability of different application configurations
as well as the predictability of reconfiguration costs. Moreover adaptation strategies need to
be developed assuring properties like the stability degree of a reconfiguration decision and the
execution optimality (i.e. select reconfigurations accounting proper trade-offs among different
QoS objectives). In this chapter we will present the basic points of a novel approach that lays
the foundations for future programming model environments for time-critical applications
such as emergency management systems.
The organization of this chapter is the following. In Section 2 we will compare the existing
research works for developing adaptive systems in critical environments, highlighting their
drawbacks and inefficiencies. In Section 3, in order to clarify the application scenarios that
we are considering, we will present an emergency management system in which the run-time
selection of proper application configuration parameters is of great importance for meeting the
desired QoS constraints. In Section 4we will describe the basic points of our approach in terms
of how compute-intensive operations can be programmed, how they can be dynamically
modified and how adaptation strategies can be expressed. In Section 5 our approach will
be contextualize to the definition of an adaptive parallel module, which is a building block
for composing complex and distributed adaptive computations. Finally in Section 6 we will
describe a set of experimental results that show the viability of our approach and in Section 7
we will give the concluding remarks of this chapter
Scientific Workflow Scheduling for Cloud Computing Environments
The scheduling of workflow applications consists of assigning their tasks to computer resources to fulfill a final goal such as minimizing total workflow execution time. For this reason, workflow scheduling plays a crucial role in efficiently running experiments. Workflows often have many discrete tasks and the number of different task distributions possible and consequent time required to evaluate each configuration quickly becomes prohibitively large. A proper solution to the scheduling problem requires the analysis of tasks and resources, production of an accurate environment model and, most importantly, the adaptation of optimization techniques. This study is a major step toward solving the scheduling problem by not only addressing these issues but also optimizing the runtime and reducing monetary cost, two of the most important variables. This study proposes three scheduling algorithms capable of answering key issues to solve the scheduling problem. Firstly, it unveils BaRRS, a scheduling solution that exploits parallelism and optimizes runtime and monetary cost. Secondly, it proposes GA-ETI, a scheduler capable of returning the number of resources that a given workflow requires for execution. Finally, it describes PSO-DS, a scheduler based on particle swarm optimization to efficiently schedule large workflows. To test the algorithms, five well-known benchmarks are selected that represent different scientific applications. The experiments found the novel algorithms solutions substantially improve efficiency, reducing makespan by 11% to 78%. The proposed frameworks open a path for building a complete system that encompasses the capabilities of a workflow manager, scheduler, and a cloud resource broker in order to offer scientists a single tool to run computationally intensive applications
- …